Chat room skeleton

[lawrence-forooghian]

Replacement for ECO-4901 so that we can discuss / link in the open. Text of that issue:

Awaiting on a spec from the Chat-JS team but current understanding:

The room lifecycle manager is the most complicated piece when accounting for the implicit attach/detach requirements. This task is responsible for making a simple attempt at attaching and detaching to rooms, without additional complexities uncovered in the spec. They will be tackled in a later task.

┆Issue is synchronized with this Jira Task by Unito

[lawrence-forooghian]

I misunderstood the scope of this task; I thought it was to implement Andy’s spec in https://github.com/ably/specification/pull/200/. That's not what it is. The idea is to implement the following:

• Rooms.get to return a room
• and then Room.attach() will then attempt to attach to all of the channels listed in https://ably.atlassian.net/wiki/spaces/CHA/pages/3083501593/CHADR-025+Chat+Permissions+and+Implicit+Permissions+for+Realtime+Channels, succeeding if and only if all of these calls succeed
• ditto for Room.detach(), detaching from the channels
• emit ATTACHED and DETACHED room status updates if attach / detach method succeeds, respectively

[lawrence-forooghian]

Also we won't implement this in the example app as part of this task; will revisit at start of next sprint where hopefully the skeleton of the example app will have been built out.