Allow marking projects as "archived"

[facutuesca]

What is this?

Following the discussion here, this PR shows what the implementation could look like for adding "status markers" to projects.

Specifically, this PR allows changing a project's status to "Archived".

Details

The implementation is straightforward, since a Project.lifecycle_status field already exists (to mark a project as quarantined). This change adds a new "archived" value for that field, and adds the UI so that users can change the project status (only for "archived" and "no status": users should not be able to quarantine a project nor modify a quarantined project).

Even though the issue mentioned above proposes more statuses ("deprecated", "finished", etc), those can be ambiguous and overlapping, and would require further discussion to define clearly. "Archived", however, is already widely used on GitHub repos and its meaning should be easy for users to understand:

You can archive a repository to make it read-only for all users and indicate that it's no longer actively maintained. You can also unarchive repositories that have been archived

On PyPI, this could also mean disallowing uploads after a project has been marked as archived, but this PR only implements the UI changes and adds the new field. Adding restrictions based on the status should be done in a future PR.

Screenshots

Project settings

Project landing page

cc @woodruffw @miketheman

[miketheman]

Generally, looking good, thanks for scoping it down to a single lifecycle status.

I think something good to add to the owner-facing management page would be a suggestion to publish a new release with a readme update or something to point folks where to go next.
Prior ideas have been to allow user-submitted text in the form, but I like that less, since then we have to figure out where to store that.

I think a warning modal popup confirmation might also be in order when archiving would be a good idea to prevent misclicks.

This also doesn't appear to block users from making further releases to an archived project - is that intentionally excluded? In my head, once Archived, it's in read-only mode - similar to GitHub's Archived.

[miketheman]

I also just realized - this probably needs some added notation in the Admin UI/ability to change there as well. I didn't see anything in scope here yet.