Get role from HTTP header
Add role to tag query
Add role to type query
Add role to artefact query
Bump odi_content_models
Fix all the tests
Add role to artefacts query
Add role to tag query
Fix curated_list tests
Add role to type query
Set role in GET request, rather than header
Get the default role from the ENV

Because generalisation and reusability
Merge pull request #62 from theodi/feature-filter-by-role

Filter content by role