[FR] implement webhooks for common git hosting sites

[blaggacao]

Role model: https://www.runatlantis.io/

[cloudnautique]

Yeah, this is certainly makes sense as a general purpose TF runner. Our initial usecases are more limited to some very specific and controlled models.

One thought I have had is to layer Argo and Argo events on top of this. That would provide a few things like a UI, workflow and eventing.