[MP] Change game filters to display mods.  Partially from zturtleman/spearmint. Thanks zturtleman.
Mods need to have pk3 + description.txt in mod folder to be displayed, same as the Mods menu.
Basegame is included in mods menu if running with jamp engine and OpenJK ui module.
The changes earlier to FS_GetModList includes basegame in modlist with OpenJK engine.