Introduce Row Level Security API in the Admin

As part of this pull request ...
- [x] Don't show delete button if user does not have ability to delete the row
- [x] Don't show the save button if user does not have ability to update a row
- [x] Don't require ROLE_ prefix for roles
- [x] Consider adding ability to maintain permissions in the admin (not entity permissions)

API should provide
- [x] hook for modifying the fetch
- [x] hook for validating that a given record is "updatable" or "deletable"
- [x] hook for validating that an update, delete, or ~~insert~~ operation passes row-level-security