CustomBanners

This is for version 1.37.3.
Let me know if something isn't working properly, not much testing was done.

Require SiraUtil, BeatSaberMarkupLanguage and AssetBundleLoadingTools.
Make sure to grab those for the right version on BSManager.

You can find banners in the BSMG discord, #banners channel.

Full Changelog: 0.1.5...0.1.6