Added ag-form to authorizations screen

- Not terribly likely to ever trigger, but will handle errors now at least.
Reviewed Authentication input filters

- Ensured all are using init() (which will allow usage of custom inputs,
  filters, and validators if we decide to use them later)
- Ensured proper items were tested
- Added validators for htdigest, htpasswd, dsn_type
- CS (docblocks, remove extraneous whitespace, etc.)
- Normalize tests:
  - pull input filters from factories (so that init() is triggered, and to get
    default validator/filter plugin managers)
  - names of tests/providers (IsValid, IsInvalid)