maintenance release

• improve the way channels are managed in monoco:
  • to create a channel: users have to override MonocoChannelEvent schemas and create their own channel.
  • to send a message: users just need to send an event (no more need to call send method of channel component).
  • to listen to a message: users just need to listen the event on their channel (no more need to call listen method of channel component).
• remove channel component,
• update MonocoChannel schemas,
• add MonocoChannelEvent schemas,
• improve metamodel module api for inheritance,
• update jsdoc.