Add edit support for some legacyrole fields.

[jctanner]

A lot of the old legacy roles had their github_user, github_repo, repository.name, namespace.name, name changed over the years. We need a way to alter those fields from the API as people change the source data.

This PR does some hacky things because the data is still all in the json fullmetadata column. In a future PR I want to migrate all the important keys out to 1st class model fields and apply proper constraints.

[jerabekjiri]

I'm able to edit original_name in the repository, is that intended?

[jctanner]

That's a good question. I think longterm, no you shouldn't be able to. For the short term though, we need to be able to set that based on the old api data.

[jerabekjiri]

EDIT:
with cURL it works fine

curl -X PUT \                                                                                                                        
-H "Content-Type: application/json" \
-d '{"username": "test" }' \
--user "admin:admin" \
http://localhost:5001/api/v1/roles/1/

{"username":["Unexpected field."]}

Updating some values like username or id in browsable API throws

[jerabekjiri]

LGTM

but question: we don't allow updating tags or description, AFAIK that happens when a user creates the role and to update, he has to create a new version with updated desc and tags?

[jctanner]

@jerabekjiri yep, description and tags will come from the meta/main.yml at [re-]import time. The editable fields in this PR were selected because they directly affect imports and installs.