feature(database): Clean up the database model significantly

* Unifies relationships + acls into "lists"
* Dropped annotations in favor of either entities or lists
* Dropped river in favor of activity-type entities
* Dropped private settings in favor of metadata
* Dropped config in favor of metadata
* Renamed datalists to config
* Entities only have a type, not a type and a subtype
* Entities can be in several different states: drafted, published, updated, and deleted
* Merged name, summary, and url fields into the entities table
* Added an alias field in entities for human-friendly names
* No more container_guid -- use lists instead
* Renamed owner_guid to creator_guid
* Subtype table no longer tracks what class to instantiate -- was horrible idea to begin with...
* All tables are InnoDB w/ comments to set up foreign keys where appropriate
* Time fields are timestamps, not just ints
* Dropped site, object, groups, and users tables in favor of metadata
* Metadata stores values denormalized

DO NOT MERGE