Ansible/Warden-Filer-Receiver: fix installation

Repository path for both Ansible roles is now CESNET of Gitlab.

For Ansible/Warden-Filer-Receiver, there are more fixes. The main task file now:

• creates the bin directory (default /opt/warden-filer)
• creates the needed /run and /var/lib directories
• copies files properly after fetching from Git
• applies executable permission to the init.d script
• creates main binary symlink at /usr/local/bin/warden_filer.py
• creates /etc/default/warden_filer_receiver file in the correct path