2023-January-05 - 2.6.14256

Lobby: wire a 'lobby-message' to front-end (#11175)

* Lobby: wire a 'lobby-message' to front-end

To replicate 2.5 functionality, this is a partial iteration
on the backend to send a custom message to users when they
login. Previously this message was stored in the lobby
servers YML file (now it will live in database instead)