Add ModSourcesMenu.cs

[DarkTerraYT]

Adds the Mod Sources Menu, a menu containing all your mod sources (that being, the ones inside of your mod sources folder designated in MelonSettings.cs).

Has a few useful things such as searching, open folder button, and an open project button. You may also refresh the menu if you've added a new mod source.

Shows the name of the mod source, as well as the location of it.

Would find the first image called Icon.png to use as the icon, but the sprite doesn't load for it ¯_(ツ)_/¯

Oh yeah, also adds a helpful method to ModHelperText, EnableAutoSizing. Used to enable auto sizing, and optionally max font size/min font size.