Webhook integration

[darekkay]

From #13:

Basically people use webhook to get the latest blog post, build status etc. So thinking of generalised panel for this, given it should be cachable. If it's okay for you , iwould try to add. But i am not expert on front-end side (espcially react)

A simple server webhook receiver endpoint should be easy to integrate, but:

a) There's currently no data persistence on the server-side (except a memory-only request cache).
b) Currently, the client would still need to poll the data, because there is no server-to-client push mechanism in place.
c) There's no user management right now. Any data received by the webhook would be available by everyone (not a big issue when self-hosted)