Round System - Extend funcionality

[joaoburatto]

Goal

Expand the round system to support round start cancelling, and player "readyness".

Acceptance Criteria

• [ ] A user can set to be ready or cancel ready in the lobby.
• [ ] User "readyness" only exists during the warmup phase.
• [ ] A admin user can cancel the warmup.
• [ ] Warmup cancelling is networked.
• [ ] User "readyness" is networked