Add "framework" as a category

[Jorge Castro]

We'd like to have a separate category for Rails, Node, Django, etc. and all kinds of "frameworky" things that developers would use.

[Richard Harding (rharding)]

This requires a few things.

- New icon for the new category from design
- Updating the charm proof tooling to allow it as a valid category
- Make sure the back end can support the new category as valid
- Update the front end to add it to the list so it's rendered.

[Gary Poster (gary)]

This got lost in the shuffle. Since no one has raised recently, and we have a gazillion other priorities, I'm marking this low, but feel free to fight back. :-)