Implement a watch_game streaming websocket api endpoint

[adrian-golian]

Set up a websocket api endpoint to allow clients to connect and be updated with game changes when they happen.

Using:

• API Gateway websocket API
• $connect and $disconnect Lambda integrations
• DynamoDB connections table
• DynamoDB stream (from the games table)
• A game state update Lambda triggered by the stream

[create-issue-branch[bot]]

Branch issue-182-Implement_a_watch_game_streaming_websocket_api_endpoint created!