add loaddata.test make target

add `needs_author`, `requires_express_permission_for_publication` and `url`

update LicenseSerializer and license fixture

- replace LicenseType with License model, update fixture, serializers, views, and urls

Closes: #167

This reverts commit 753af8b4.

Closes: #151

Closes: #150

`biography` is not nullable.

This fixes aura#174

- Replace ImageField with ForeignKey reference to Image
- Update `program/show.json` fixture
- Update serializer to refer to Image and allow null

Since this may lead to errors while initialazing the container.

Closes: #163

Closes #142

- replace cc0: No Rights Reserved with pd: Public Domain
- prefix the Creative Commons License names with `cc-`
- add gfdl: GNU Free Documentation License

- updated the fixture
- updated the serializer
- updated some views