feat(core/managed): add proper support for skipped, approved artifact states

[erikmunson]

We recently came to the realization that the approved and pending states an artifact can have in a particular environment were a bit conceptually overloaded, because they both contained versions that had been skipped over due to later versions becoming available. This meant it was very challenging to explain what approved and pending meant in the UI because a version could either be in a state of approved-ness / pending-ness, or it could've been skipped and have no chance of ever being deployed.

We've now split out a totally new state — skipped — to help clarify the semantics of the other two states, freeing up approved to mean "this version is about to start deploying" and pending to mean "this version is actively under consideration for deployment, but hasn't been chosen yet". This change adds full-fledged support to all three of these statuses, as the inherent confusion had prevented us from adding useful UI treatments until this point. Looks like this:

Pending:

Approved:

Skipped (version info available):

Skipped (no version info available):

Icons are coming soon (the approved one is also temporary), but wanted to get this out in advance of having iconography.

(cc @gcomstock)

[vigneshm]

Looks great!

[luispollo]

❤️ it!

For another PR, I still think we could change "Already deployed to previous environment X" to "Dependency on environment X passes" or "Dependency on environment X satisfied", though. 😄

[erikmunson]

I did call that out as an alternative we very well might move to depending on how the overall experience is feeling, but for now I'm sensitive to keeping the voice and tone of the foundational/core constraint cards fairly consistent with each other. I'd likely rework the tone of some other cards along with it if we end up going that direction.