This adds the ability to the git-remote-helper to open and update
patches via a `git push` to the magic ref `refs/patches` and
`refs/heads/patches/<patch-id>`.
The main change is that we had to move away from offering the `connect`
capability in the remote helper, to offering `push` and `fetch`
individually.
To get a feel for how this works, see the `rad-patch-via-push.md`
example.
This command announces refs to peers and waits for them to be
in sync.
Adds a subscribe method to `Handle` so that we can get the events
from the seed to allow us to confirm that the configured seeds fetched
from us.
Alexis Sellier
xphoniex
Slack Coder