Adding [Gitpod](https://github.com/gitpod-io/gitpod) allows us and others to easily start a complete Woodpecker setup and development cloud IDE. It starts a Woodpecker server, agent and a preconfigured Gitea instance. You can login at Gitea with `woodpecker` and `password`.
- migrate step conditions back into pipeline syntax, but show 2-4 level in toc to be able to see `when` keywords
- create new backend section in admin docs
- update docusaurus
- remove prefix docker of container / container-image where possible
- replace terms SCM, VCS, Github with [forge](https://en.wikipedia.org/wiki/Forge_(software))
- add darkmode favicon variant
