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

contrib/ansible/warden-filer-receiver/defaults/main.yml

 ---
 server_admin: "{{ root@inventory_hostname }}"
 warden_filer_bin_path: /opt/warden-filer
+warden_filer_lib_path: /var/lib/warden_filer
+warden_filer_run_path: /run/warden_filer
 warden_client_cert_path: /etc/ssl/certs/warden.cert.pem
 warden_client_key_path: /etc/ssl/private/warden.key.pem
 warden_client_id_store: /var/lib/warden_filer/warden_filer.id