License code & content permissively

- GPLv3 for code
- CC-BY-SA 4.0 for content
- Add credits to README

Working on openrightsgroup/cmp-issues#15
Move license files to project root
Move license & credit info into the right README
License code & content permissively

- GPLv3 for code
- CC-BY-SA 4.0 for content
- Add credits to README

Working on openrightsgroup/cmp-issues#15
Merge branch 'licensing' of github.com:openrightsgroup/blocked-org-uk into licensing
Merge pull request #56 from openrightsgroup/licensing

License code & content; add credits