Remove migrations intended to run on top of the D&D database.

Instead of assuming the app will build on the D&D database, assume it will begin with an empty database. We'll import relevant data via seeds.
Create ClericDomains.
Bring in Annotate gem.
Create Spells and SpellLevels
Seed spells
Merge branch 'refs/heads/features/seed_spells'
WIP