GitLab

Add hint to the issues with explicit dependencies

* LaTeX rule still seems not to be that stable, therefore removed from
site.yml
* Rename all versions to lasarchiv1 to be consistent
* Update SSH playbook of common rule to open the ports in the firewall

* Clean up hosts file and order roles in README

* Add -K option

* Add links to ansible-pull
* Add dependencies

* Update branches text

* Update the `ansible-pull`-procedure for the initial installation of a
computer

A readme including basic ansible knowledge to install a system and to
maintain this repo