Configuration and deployment updates

A few boring backend changes in preparation for server upgrade to Debian 10, deployment fully managed through Ansible and future changes to multiple institution hosting that can make use of Python 3.6 features.

• Vagrant based development environment updated to a single step live instance
• Database migrations adapted into the Flask CLI to remove the need for separate management of Alembic
• Lots of updates to Ansible deployment to make it fully comprehensive (dev/test/live working)
• Use Flask.config for configuration management
• Database engine managed at the application level
• Celery makes use of Flask for configuration management and database
• Use Black with default options
• General cleanup