Update GH sync to support v2 protocol

[josephjclark]

The GitHub Sync UI and action are configured around CLI sync v1 - the openfn pull and openfn deploy commands

v2 CLI sync is designed to make the github experience much better by writing out workflows to the file system and using neater "state files".

The UI makes assumptions and explains concepts that only apply to v1, such as the path to config.json.

We should update this UI to enable use of v2 sync, with more relevant text and instruction.

‼️Super important! v2 only allows one openfn.yaml and one workflows folder. You can set up multiple syncs to a v2 repo, but only one pull (ie, only one connection that uses Save & Sync to trigger a pull into the repo and commit). You can deploy a single project to multiple places though. Because of this we might want to add a one-way flag to prevent save and sync.

We don't actually need to change the action - it'll work just fine with the v2 sync if there's an openfn.yaml file in the repo. We might want to reengineer around the new APIs but I don't think there's any value.

Saying that, the initial sync action for v2 needs to initialise an empty project.yaml file - so maybe we do need a v2 action.

[josephjclark]

@brandonjackson @theroinaochieng I've been reminded to add this one more issue that's required before launch - we want github sync to use the v2 sync by default

[brandonjackson]

👍 cc @theroinaochieng