Change workspaces list filter, garbage collection, and pinning

[gtsiolis]

Problem to solve

Filters: The dashboard redesign back in #3426 split the workspaces list into Active & All. The split was introduced to help educate users about the ephemeral nature of workspaces as users kept coming back to restart stopped workspaces that contained obsolete code. See also Gitpod's Product Vision and relevant blog post. 🌀

Garbage Collection: Regardless this split, users still find it difficult to keep in mind the active garbage collection that automatically deletes unpinned workspaces that have been stopped for more than 14 days, even if with the new non-dismissible alert on the top of the stopped workspaces list. ♻️

Pinning: Thus, pinning workspaces became more like a habit users fallback to maintain a peace of mind. ✌️

Besides all the above, we're still receiving a lot of requests from users to restore auto-deleted workspaces, and more.

Proposal

Things we could try in smaller iterations as MVC (minimum viable changes) or altogether in one step:

1. Keep all workspaces with pending changes in the Active workspaces list. Potentially auto-pin to avoid confusion.
2. Never garbage collect any workspace with pending changes.
3. Remove the pinning functionality altogether.

[svenefftinge]

We cannot never garbage collect, because that would blow up our storage usage. We've been there.

How about moving both active and inactive to one page, where we have a thin separator that starts with the garbage collection warning?

Something like this:

[atduarte]

Right now, there is a recurrent issue that our students think Gitpod is deleting their Workspaces, when in reality, the workspaces are not deleted but hidden... users need to click on the "filter" option and choose "all" to be able to see the hidden workspaces.
The filter says "active" but I don't know what active means, if I don't have any running workspaces the filter stills filter some of the workspaces, what's the criteria to filter here?

More info at #5402

[gtsiolis]

Closing as this has been resolved in #5555. Future improvements could include merging the unified workspaces list (see #5861), removing the pinning functionality, re-introducing the global workspaces list, and more.