Some reorganisation

Some reorganisation

Fix repmgr version (paunin#98)

Fix barman_check_is_ok metric (paunin#90)

Feature/barman metrics (paunin#81)

* Add space requirements to RECOVERY.md

* Ensure correct permission for ssh keys even if daemon is not enabled

* Barman doesn't require running PG to start

* Add .swp to gitignore

* Add metrics for Barman

* Add prefix to metrics. Updated README.md

Fix README, drop minor version in barman image (paunin#80)