Draft: Add promtail role

This adds an ansible role for Promtail a log collecting agent which pushes logs from the host to a loki instance.

Things to do before merging:

• Merge role/monitoring to have a complete solution as the monitoring role provides loki
• Figure out SELinux situation, e.g. watching a dir labeled 'var_log_t' without running as 'spc_t'
  • simply run with selinux label seperation disabled, better would be a custom policy but i'm lazy
• Figure out why ProtectSystem=full in the service file leads to commands like podman ps to error out as soon as promtail is running
  • This blocks podman from setting up the cni network at (/run/netns)