Archive projects

It would be great if we could archive deployments similar to archiving GitHub repositories.

Sometimes one wants to keep a deployment without intending to change it in the future, so deletion is not an option. Currently, those deployments fill up the "Projects" page. Also they risk being accidentally broken because Deno Deploy doesn't block any changes (e.g. commit push).

Start by reviewing how deployments are represented and listed on the Projects page. Define what an archived deployment should preserve, how archiving and unarchiving work, and which changes must be blocked. Done means archived deployments remain available without cluttering the main list and cannot be accidentally modified.

Written by the indexing model from the issue text.