Add nullable license field to Projects model

[hudson-newey]

Add nullable license field to Projects model

Given that projects can be publically available for viewing, users have commonly associated usage rights and licensing information with the projects. However, with existing API capabilities, this information is usually encoded in the description field.

The addition of a specific license attribute on projects will allow uses to either: Reference an SPDX license code or insert a custom license as free form text.

Changes

• Adds a license filed to project models

Issues

Fixes: #289

Problems

None

Visual Changes

None

Final Checklist

• Assign reviewers if you have permission
• Assign labels if you have permission
• Link issues related to PR
• Remove/Reduce warnings from edited files
• Unit tests have been added for changes
• Ensure CI build is passing

[atruskie]

looks good.

Like we discussed, at some point in the future it might be nice to know programmatically which projects use an open license, server side. But for now, we don't have a clear use case for the added complexity and I anticipate we can do an uplift later when it is needed.