Remove menu background; add perf test resources

Remove hardcoded background-color from MainMenu.uss. Add PerformanceTestRunInfo.json and PerformanceTestRunSettings.json (plus their .meta files) to store performance test metadata and settings. Update ProjectSettings.asset LFS oid/size to reflect project metadata change.

Assets/Game/Menus/MainMenu/MainMenu.uss

@@ -3,7 +3,6 @@
     flex-direction: column;
     align-items: flex-start;
     justify-content: center;
-    background-color: rgb(43, 0, 87);
     overflow: hidden;
     padding-left: 6%;
     right: 0;