Codehost webhooks setup wizard

Created by: malomarrec

User problem

Setting up webhooks is hard. There are many steps and failure points and the docs are confusing. The site-admin json input form does not help.

This is not urgent, as the main root cause for users not setting up webhooks is that they don't know about it #24310 (closed). Once aware, they manage to get through the process. In the long run though we'd like to make it really easy for site-admin to setup webhooks.

Proposal

• A webhook wizard helps users setup and validate codehost webhooks
• When webhooks are not setup for a codehost, visual cues alert admins