Changes

pySim-shell: renovate version command

In case pySim-shell is used directly from the git repository (not
installed via a package manager), the version command fails with an
exception because pkg_resources.get_distribution('pySim') fails.

Let's renovate the version command and migrate from pkg_resources to
importlib.resources. There are many users and developers out there who
retrieve pySim-shell directly from the git repository and not via pip3.
To accommodate for that, let's check if pySim-shell.py is located in a
git repository and if so, let's display the HEAD commit hash instead.

Since the version of the currently installed pyosmocom version also
plays a critical role, let's display the pyosmocom version as well.

Related: OS#6830
Change-Id: I2b9038f88cfcaa07894a2f09c7f5ad8a5474083d