Delete GL Groups object
Per today's sync, GL groups object is likely not necessary. Need to:
- Delete from models.py
- Update Project attributes to remove GlGroups FK
- Update Project save definition to remove GLGroup related logic
- Update Project.short_name_with_namespace field so that it no longer calls GLGroups
- Check all templates for any references to GLGroup object or methods
- Run all tests and fix any broken tests.