Move 1.6.x mod config to their own folder

and add a folder for 1.7.x mod config files
Add Twilightforest mod configs, made by joulesbeef
Update twilightforest.blocks.yml
Add an UpgradeManager
Prepare for UUID update
Add u.uuid here
Deprecate methods in ExperienceAPI
UUID Conversion stuff
Deprecate PlayerProfiles relying on names
Add hidden options for uuid conversion
UUID flatfile stuff
Save and load profiles using UUIDs
fall back on usernames if neccesary
Update playername in database when a name changes
Load UUID with SQL
Update to UUIDFetcher v3
Save if uuid conversion is complete in convert.yml
Add saving of UUIDs (used in the UUID Fetcher update task)
Add a new fallback method that does the exact same thing; add it when the retry on getting a UUID player would have failed twice
Check for uuids instead of usernames when loading a player
Use UpgradeManager instead of ConvertManager