Remove custom Cobbler CLI and use the entry_points from setuptools

[SchoolGuy]

Does what the title says

[SchoolGuy]

Okay some requirement for the generated script is not matched in some environments. I will investigate but this is a good step for ensuring the setup is working which we didn't have before...

[SchoolGuy]

Okay so Leap 15.2 and Debian 10 do not include the Python distribution for mod_wsgi. This means when installing a packaged version of Cobbler this will fail. I am currently trying to fix this for Leap 15.3 but for Debian the only solution will be to do a pip install mod_wsgi. This is unfortunate but I don't see any other option which is doable. Removing mod_wsgi from the project requirements of pip is possible but in my eyes not a experience in case you forget to install it before installing Cobbler.

[SchoolGuy]

Mail to the Debian Maintainers of Apache2-mod_wsgi was sent describing the problem.

[SchoolGuy]

So I believe this PR is ready. When the SR to the SLE Codestream has gone through maintenance this will work. Nevertheless I do desire a positive response from the Debian folks to merge this.

[SchoolGuy]

So the CLI will be developed seperatly in the mid-term future, thus the script I am removing will be obsolete anyway then. Using the same approach for cobblerd is very tempting since this is also just a very thin wrapper but it appears that we are not ready for this yet. Thus I will close this PR but won't delete the branch. Maybe when Debian and Leap have fixed it we can reopen this PR.