Add endpoint to detect new recordings and update the interface

The endpoint receives events from BigBlueButton via webhooks or scripts
in the record and playback workflow.
For now it only treats the event for when a recording is ready.
When it happens, it uses action cable to update the interface dynamically
with the new recording.

config/locales/en-us.yml

@@ -48,6 +48,7 @@ en-US:
     no_recordings: No Recordings
     no_recordings_yet: No Recordings (Yet!)
     publish_recording: Publish recording
+    recording_created: A recording was created
     recording_deleted: Recording was deleted
     recording_published: Recording was published
     recording_unlisted: Recording was unlisted

config/routes.rb

@@ -31,6 +31,7 @@ Rails.application.routes.draw do
   get '/:resource/:id/join', to: 'bbb#join', as: :bbb_join, defaults: {format: 'json'}
   get '/:resource/:id/wait', to: 'landing#wait_for_moderator'
   get '/:resource/:id/session_status_refresh', to: 'landing#session_status_refresh'
+  post '/:resource/:id/callback', to: 'bbb#callback' #, defaults: {format: 'json'}
   delete '/rooms/:id/end', to: 'bbb#end', defaults: {format: 'json'}
   get '/rooms/:id/recordings', to: 'bbb#recordings', defaults: {format: 'json'}
   patch '/rooms/:id/recordings/:record_id', to: 'bbb#update_recordings', defaults: {format: 'json'}