With PR #1368 some functions are added to create and request certificates.
Based on those functions a new helper method `setup_self_signed_certificate` is created.
This should make it easy to add basic support to clients and servers for generating automatically certificates.

If can generated a private key and self-signed certificate when not already present.
When the data range of the certificate is no longer valid it generates a new certificate.

Both the examples for client and server use with encryption are updated to demonstrate the use.

"Coroutine 'set_security_string' is not awaited" it is an async function.

Those issues were not detected previously since they are linked to the
recent update of ruff to version 0.0.283, which fixed an issue in the
detection of this lint error.

* When reading Enumeration and OptionSet type definitions, also accept StructureDefinition instance.

This kind of type definition is "unclean" but not strictly forbidden by the standard.
Requires guessing of actual enum values:
- Count starting at 1 for Enums
- 0x1, 0x2, 0x4, ... for OptionSet

* add test for OptionSet defined via StructureDefinition

* load_enums: On unexpected errors, skip entry with error message

* fix test if not run in isolation

when subscribing to ConditionType

* Test for strings that aren't arrays, but start with a bracket

* Fix array-detection in string_to_val

* create private keys
* create self signed certficates
* create certifcate signing requests
* create ca for signing csr

The helpers are:
* generate_private_key
* generate_app_certificate_signing_request
* generate_self_signed_app_certificate
* sign_certificate_request

Test and example are available.

According to Part 4 - 7.10 this should be an a number that indicates how secure the EndPoint is. The number is Server implementation specific, how higher the number how saver.

* Fix for numvalues parameter in Node.read_raw_history()

* Fix for numvalues parameter in Node.read_raw_history() 2

* Update xmlparser.py

* Update xmlparser.py

* Update sync.py

add 'monitoring' and 'sampling_interval' params to subscribe_data_change in sync.py.

* Update sync.py