This commit closes #752.

With py3.10, high level asyncio API can't specify the event_loop
argument anymore.

Consequently When using thread dedicated to run the event_.loop, we now need to
instantiate object like asyncio.Lock within the thread. However, the
event loop can't be running before creating these objects as
`loop.run_for_ever()` must be the background running thread process.
Therefore we can't have "get_running_loop()" calls in object
constructors (like HaClient)
when used with executors.

Before
```
In [15]: def get_t():
    ...:     loop = asyncio.new_event_loop()
    ...:     t = T()
    ...:     loop.run_for_ever()

In [16]: class T:
    ...:     def __init__(self, loop):
    ...:         asyncio.set_event_loop(loop)
    ...:         asyncio.get_running_loop()
    ...:         self.l = asyncio.Lock()
    ...:         print("Lock created")
    ...:

In [17]: t = Thread(target=get_t);t.start()

Exception in thread Thread-9:
Traceback (most recent call last):
  File "/usr/local/lib/python3.8/threading.py", line 932, in _bootstrap_inner
In [41]:     self.run()
  File "/usr/local//lib/python3.8/threading.py", line 870, in run
In [41]:     self._target(*self._args, **self._kwargs)
  File "<ipython-input-32-c4a1ea4cfdac>", line 3, in get_t
  File "<ipython-input-39-ebeae10dd173>", line 4, in __init__
RuntimeError: no running event loop
```
After

```
In [15]: def get_t():
    ...:     loop = asyncio.new_event_loop()
    ...:     t = T()
    ...:     loop.run_for_ever()

In [16]: class T:
    ...:     def __init__(self, loop):
    ...:         asyncio.set_event_loop(loop)
    ...:         self.l = asyncio.Lock()
    ...:         print("Lock created")
    ...:

In [17]: t = Thread(target=get_t);t.start()

Lock created

```

This reverts commit 49fefd4d.

fix add properties/variables in _create_custom_type

* Update xmlimporter.py

This allows to load information about newly created data types in the same import process

* Update xmlparser.py

with this we can set the value to newly created datatypes

* Update ua_utils.py

This is conform to the I40AAS nodeset enumerations, e.g. given enumeration as "AccessPermissionRule_0" specifying the type and the integer

* Update xmlimporter.py

small changes due to necessary async and await

* Update xmlparser.py

switched from try/catch to check

Follow-up of #711
Make sure calling disconnect is safe when connection isn't established
or half-established (i.e: protocol/transport exist but session is not
ready).

Test1
Call to disconnect is safe when there's no existing connection
```
> python -m IPython
Python 3.10.0 (default, Oct 13 2021, 06:45:00) [Clang 13.0.0 (clang-1300.0.29.3)]

In [1]: import sys; sys.path.insert(0, "~/Documents/github/opcua-asyncio"); import asyncua; c = asyncua.Client(url="opc.tcp://localhost:4840",timeout=10
   ...: );

In [2]: await c.disconnect()
close_session but connection wasn't established
close_secure_channel was called but connection is closed

In [3]:
```
Test2

Calling to disconnect is safe when there's no session established.
To simulate this, I add delay to the server internal_session on session
creation. I check that the client connects and disconnect from the
server logs. Finally, the client doesn't raise any error.
Ad delay to the internal server
```
> python -m IPython
Python 3.10.0 (default, Oct 13 2021, 06:45:00) [Clang 13.0.0 (clang-1300.0.29.3)]
In [1]: import sys; sys.path.insert(0, "~/Documents/github/opcua-asyncio"); import asyncua; c = asyncua.Client(url="opc.tcp://localhost:4840",timeout=10
   ...: ); import threading; import asyncio;

In [2]:

In [2]: async def connect(c):
   ...:     await c.connect()
   ...:

In [3]: async def disco(c):
   ...:     await c.disconnect()
   ...:

In [4]: L = await asyncio.gather(connect(c), disco(c))
close_session but connection wasn't established
close_secure_channel was called but connection is closed

In [5]: quit;
```

According to the logs of the recent test failure, there's a small window when we test the connection is established where we have a socket connected but don't have the session created yet, and this is throwing exception when trying to disconnect because the renew loop is not yet created.

This is caused by the HaManager (in charge of connecting/reconnecting the clients) running in its own task, thus we're not in the usual await connect(); await disconnect() scenario.
This can also arguably be fixed at the client level by checking if
the renew loop exist on disconnect.

The HaClient is missing from the PyPi package:

```
[/tmp]> curl https://codeload.github.com/FreeOpcUa/opcua-asyncio/tar.gz/refs/tags/v0.9.91 -s -o v0.9.91.tar.gz
[/tmp]> tar xvf v0.9.91.tar.gz > /dev/null 2>&1
[/tmp]> cd opcua-asyncio-0.9.91/
[/tmp/opcua-asyncio-0.9.91]> python setup.py install > /dev/null 2>&1
[/tmp/opcua-asyncio-0.9.91]> find build/ -type f |grep -i ha
build//lib/tests/test_ha_client.py
build//lib/asyncua/ua/uaprotocol_hand.py
```

The build rules only look for the packages via
(`find_packages`) in setup.py, making the ha client sub-directory a
package fixes it:
```
[/tmp/opcua-asyncio-0.9.91]> rm -rf build/
[/tmp/opcua-asyncio-0.9.91]> cat asyncua/client/ha/__init__.py
"""
Pure Python OPC-UA library
"""

from .ha_client import HaClient, HaMode, HaSecurityConfig, ConnectionStatesing
[/tmp/opcua-asyncio-0.9.91]> python setup.py build > /dev/null 2>&1
[/tmp/opcua-asyncio-0.9.91]> find build/ -type f |grep -i ha
build//lib/tests/test_ha_client.py
build//lib/asyncua/ua/uaprotocol_hand.py
build//lib/asyncua/client/ha/__init__.py
build//lib/asyncua/client/ha/common.py
build//lib/asyncua/client/ha/ha_client.py
build//lib/asyncua/client/ha/reconciliator.py
build//lib/asyncua/client/ha/virtual_subscription.py
```

Changing the HaClient test import path to ensure no regression.

Avoid running introspection code every time a message is deserialized

See https://github.com/FreeOpcUa/opcua-asyncio/pull/700

* Reduction of network access

Cache the nodes of potentially multiple-used FileType methods.

* indentation error corrected

* Add low-level file system functionality

* Added examples for the use of ua_file_transfer.py

In the following you will find examples for the use of the
classes UaFile and UaDirectory and how to handle typical uaerrors.
see: ./asyncua/client/ua_file_transfer.py.

The OPC UA File Transfer specification can be found here:
https://reference.opcfoundation.org/Core/docs/Part5/C.1/

* pylint optimized - ua_file_transfer.py 

pylint optimization of file ua_file_transfer.py.
=> Your code has been rated at 10.00/10 (previous run: 10.00/10, +0.00)

* pylint optimized - client_ua_file_transfer.py

pylint optimization of client_ua_file_transfer.py.
=> Your code has been rated at 10.00/10 (previous run: 10.00/10, +0.00)
Co-authored-by: Curious Crook <privat@nowhere.org>

Augmented assignment statements became available with Python 2.
https://docs.python.org/3/whatsnew/2.0.html#augmented-assignment

Thus improve three source code places accordingly.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>

The test suite used to create files in the CWD, which then showed up as untracked files in git, and would cause the tests to fail when ran successively with different users.

This commit makes successive test runs independant from each other

* 3x performance improvement for serialization

Instead of re-inspecting the type metadata everytime an object is serialized,
create a single serialization function for each type and just call it when an instance is serialized

* pre-compute uatype array serializers

* Make VariantTypeCustom instances valid cache keys

VariantTypeCustom instances can be used as cache keys for serialization functions

* Enable the server to listen to an arbitrary IP

* Add missing doc
Co-authored-by: oroulet <oroulet@users.noreply.github.com>