Add option to update recordings individually

[daronco]

Add an option to the management list of recordings (the list of recordings and/or the edit page of a recording) to update that recording. This option should send a getRecordings to the server for this specific recording and update it in the database with the info received.

There are already fetch_recordings routes for servers and rooms, but not for recordings, so this would need an implementation in bigbluebutton_rails.