Schema and some model changes for new permissions

Inconsistent schema.  Stuck on excerpts.  Forgot what a mess they are.
SlotAsset work for new permission, dump slot thumbs for now
WIP: permissions, party controller updates
WIP: permissions, misc, straying into views
Some basic messages for the new permissions levels
WIP: permissions, now compiling
Controllers to set full-asset excerpts
Check excerpt classification setting
Remove slotThumb from angular
Allow volume access children admin

Only matters if member is admin anyway, so what does that hurt
Synchronize schema: permissions evolution
Fix some (but undoubtedly not all) sql for permissions
A couple more sql fixes and basic js

For now we're assuming that all excerpts are displayable (image or video)
Merge branch 'excerpts' into permissions
Add some auth titles, tweak messages
Fix some volume access references for list/overview
Fix browser permission check; remove unused auth apply fields
Move pending auth notice to messages
dateModel directive for easier validation; authGrantForm does new way mostly
Merge branch 'permissions' of https://github.com/databrary/databrary into permissions

Conflicts:
	conf/messages