Implement rival registration, profile responses, and Web UI controls.
The UI is functional only; visual design and polish are not included in this change.
* Added a leaderboards page to the WebUI. This page displays the rank of all players per game and version, ordered by Skill rating.
* More code cleanups to Profiles.ts
Refactored and cleaned up several functions.
MDB loader now logs the number of loaded songs available to GF and DM.
MDB: Fixed "is_secret" field being ignored (always set to false)