Expand "Matchmaker API" to include get/set Game Modes and get Builds. [QoL]

Just a proposed quality of life change to the Matchmaker API. Currently only depending on the Matchmaker API limits a server's ability to read game mode and build info from PlayFab. This means the server has to also depend on the full blown server api or replicate the info into a separate config for the matchmaking server. It would be nice to have custom matchmakers at least be able to read game mode/build info from PlayFab when they start up.