Initialise repository structure and placeholder files. Generic functionality works i guess, need to come up with a better solution for compose templates

roles/arr/README.md

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+# arr
+
+Deploys a LinuxServer.io Arr stack with Prowlarr, Sonarr, Radarr, Lidarr, and
+Bazarr. Override `arr_services` to add or remove services.
+
+Tags: `arr`, `config`, `compose`, `firewall`.
+