See merge request nexedi/slapos!1267

Move hardcoded values to default values.
Source the whole content of the data-to-vm parameter.

See merge request nexedi/slapos!1266

This take another approach at c5cd4e06 (component/glib: set --with-python
to generate scripts with slapos python, 2022-09-20) because this python
might exceed the limit of shebang lines, that change was bad because it
brought back the problem that we fixed in 6acdc8ca (glib: put the expected
python in $PATH, 2019-12-18)

Now that component/defaults.cfg set the ${python:location}/bin in $PATH,
we can assume that python is always in $PATH. The problem with python3
software is that python3 does not install a "python" binary, only python3,
so we can use the $PYTHON environment variable which will be set to
python2 or python3 and that in both cases this will be a valid python
interpreter.

This re-applies 7581b668 (component/glib: remove bad file bin/gtester-report
after compilation, 2020-08-07) because with this approach that script's
shebang is just #!python3

use unshare to create new user-root namesapce to have the perrmission to
create network device, use mount to update files information of network
device in /sys(nemu)
test use iptables to manage route condition, miniupnpd to manage upnp,
brctl(nemu) to create bridge, so add them in component.

add openvpn, add babel, modify ovpn-client/server

due to outdated pypi version, nemu don't include need moudle in
setup.py, so add them in buildout

See merge request nexedi/slapos!1254

Update software/fluent-bit/software.cfg, software/fluent-bit/instance.cfg.in, software/fluent-bit/buildout.hash.cfg files

See merge request nexedi/slapos!1259

see nexedi/slapos.core!418

We were using python2 after extending python2, this explicitly set
python:part = python3

glib configure script uses by default python2.7 to substitute in scripts,
but it also supports --with-python argument. Since the scripts support
python2 or python3, we can use the full path of the python used by
buildout. This will sometimes create shebang lines like:

    #!/usr/bin/env /path/to/slapos/python3/bin/python

but this also work fine.

This replaces the following commits:
 - 7581b668 (component/glib: remove bad file bin/gtester-report after compilation, 2020-08-07)
 - 9c47f828 (componnent/gtk-2: Add python2.7 as the dependency of pango, 2022-08-18)

This removes the need for pytest-testrunner and silent warnings about
its vulnerability in software check

Instead of downloading the image every time before running the test
we pre-download all images during the software installation. This
prevents downloading ~2Go every time, which is sometimes too long for
the slapos node instance step.

Commit changed order of some parameters, which were not reflected in test
updated.

Fixes f0a57a1f