I have started the migration myself of this to Blender 2.8+.
https://github.com/Reticulatas/LevelBuddyforBlender28
This is early, but I have the basic functionality working. It's still quite crashy. If someone better at Blender Python picks this up, there is probably not much more to do to get it 100% functional.
EDIT: Looks like someone else beat me to this but didn't touch TextureBuddy - might be worth continuing regardless