RFE: use patchwork to submit a patch

[Drew DeVault]

I happen to have been working on something like this today:

https://sr.ht/x71F.png

This doesn't require any JavaScript.

I've also been working on the other side, but it's less shiny - I'm
teaching pygit2 about pluggable object db backends so that I can teach
my mailing lists to talk to my git repos, and do things like offer
expandable diffs, check mergability of patches, submit CI jobs, etc.

Some more screenshots from my work today:

https://sr.ht/3grl.png
https://sr.ht/rcsA.png
https://sr.ht/CLHm.png