feat(push): allow pushing composed components to registry

[fibonacci1729]

WIP for now to flesh out the concept.

Implements #2988

Still working to add a test but the meat-and-potatoes is ready to serve.

[fibonacci1729]

cc/ @itowlson a simple test is now included.

[fibonacci1729]

@itowlson friendly ping that this is ready for another review!

[itowlson]

First off, sorry for taking so long to get to this.

I don't really feel capable of reviewing this beyond "I affirm that Brian is not sneaking in a Bitcoin miner," but from what I can tell it seems sound, and I assume you've tested it against suitable hosts which is more reassuring than any reading of mine could be!

I did have some comments on the style and the testing - they're not blockers, but I'd like to see if they're easy to address before we merge. (And please ignore the melodramatic last comment - we've already covered that but I'm struggling to reconcile myself to the outcome!)

[itowlson]

Thanks for those changes - this feels much more readable now (at least to me!). Appreciate your patience with my niggling. If you're still comfortable with it then good to go!

[fibonacci1729]

Thanks for the review! I think i'll try to get 1 or 2 more 👀 just to spread awareness.

[fibonacci1729]

Ran make test locally and everything seems green; Also fixed a few lints that popped up in tests/