Clean up and consolidate database access

- amgut.util → amgut.connections
- consolidate AG_DATA_ACCESS into amgut.connections
- move r_server to amgut.connections
- AG_DATA_ACCESS → ag_data
- r_server → redis
- lazy-load of database connections (useful for re-using library code like
  scripts/ag does without automatically connecting to the database)
- move db_conn to the one file it's used in
- consolidate one usage of AG_DATA_ACCESS in amgut/lib/vioscreen.py up a level
  into amgut/lib/util.py
Ignore .env
Add steps for a quick-start, fixes #333
ag should be the current schema
Fix comment
Comment out dangerous insertAGMultiple
Remove duplicate __del__
Add Procfile for ease of running
Add database patch for Open Humans token