[CHA-RC1] Implement async rooms.get and rooms.release

[sacOO7]

• Implement async rooms.get('roomId') and rooms.release('roomId') operations as per spec and rooms async DR
• The current rooms.get operation is blocking in nature, this needs to be updated to async in nature as per rooms get async chat-js PR
• This affects how internal room-lifecycle-manager works and has been implemented accordingly.
• Reference impl. for the same ->

1. getRoom -> https://github.com/ably/ably-chat-js/blob/54229a40a8b2a506f36ffbb5e3a355c2e2616199/src/core/rooms.ts#L145
2. releaseRoom -> https://github.com/ably/ably-chat-js/blob/54229a40a8b2a506f36ffbb5e3a355c2e2616199/src/core/rooms.ts#L156

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