Move all Etherpad's access control from Meteor to a separated [Node application](https://github.com/bigbluebutton/bbb-pads).
This new app uses [Etherpad's API](https://etherpad.org/doc/v1.8.4/#index_overview)
to create groups and manage session tokens for users to access them. Each group
represents one distinct pad at the html5 client.
- Removed locked users' access to pads: replaced readOnly pad's access with a new pad's content sharing routine
- Pad's access is now controlled by [Etherpad's API](https://etherpad.org/doc/v1.8.4/#index_overview)
- Closed captions edited content now reflects at it's live feedback
- Improved closed caption's dictation mode live feedback
- Moved all Etherpad's API control from Meteor to a separated [app](https://github.com/bigbluebutton/bbb-pads)
- Included access control both in akka-apps and bbb-pads
Remove padIds from the closed captions MongoDB collection subscription.
Users now have to fetch the padId from Meteor when needed. Meteor is
responsible for checking the user's access level and return the
proper id.
