Updates llfloatergroups to be a lot similar to upstream
- Adds LLFLoaterGroupPicker::removeNoneOption and changes LLFloaterGroupPicker to use modern style callback
- Switched from using per ui xml string for the none entry in groups to the strings.xml one, updated and cleaned existing translations to use this.
- Changes LLFLoaterGroupPicker into an instance tracker by id, because it was already acting like one.
Updates llpanelpermissions RLVa bits and fixes last owner label never enabled
Also upgrade the file picker filters with the new extensions found
in the orginal file picker code of Singularity.
Also improve AIFilePicker a bit: added hasFilename() and now
deleting the statemachine automatically by default: it's no longer
needed to call deleteMe from the callback.