Socket clients running on alpha server can get disconnected due to timeouts

[mgaree]

The AI Manager and AI Agents can get booted from the server after long periods of inactivity. Despite sending heartbeats as normal, something about the alpha server is keeping them from being received properly and causing the server to disconnect the clients. Once the AI Manager is booted, new AI games cannot be started. Note: the heartbeat behavior on the alpha server and on my localhost differ despite running the same manually-installed packages.

Fixing the server issue is preferred, but may not be feasible. Instead, have the Manager rejoin the Lobby when it get disconnected.