Post announcement or messages to each player about cancellation?

[jimenezj8]

When a game is canceled, it should probably be reflected somewhere in the workspace so that any players who were interested or already signed up are aware. There are a few options for this:

1. Capture message IDs / timestamps for announcements in order to post a reply in the thread
2. Capture message IDs / timestamps for announcements in order to delete the message
3. Capture channel IDs for announcements in order to post a second, independent message about the cancellation
4. Just cancel the game, post an ephemeral message to the requesting user
5. Just cancel the game

This needs to be handled on app.py: cancel_game_command_handler

[jimenezj8]

This bot will:

1. Message a thread reply (and broadcast to the channel) that the game was canceled
2. Add an :x: reacji to the original announcement message