List Projects in Pro Dashboard

[garethrees]

We’ll need a jumping off point for selected Pro users to create and get to their Projects.

We’ll enable Projects on a per-user basis with a feature flag, so this area can be rough and ready for now. It would be good to add a little warning to make this clear.

For now, we’ll jam another navigation item into the Dashboard sidebar as we do for Drafts.

That will render a very basic listing of the Projects a user is an owner of, and a way to create a new Project.

The creation (https://github.com/mysociety/alaveteli/issues/8250) and publishing (https://github.com/mysociety/alaveteli/issues/8251) parts are much more important at this stage, so any extras like filtering, pagination, etc can be skipped here if we’re getting short on time.