* Add mermaid JS renderer
For feature parity with GitLab. Tested in files, issues, wiki, editor.
arc-green only does an inversion because the renderer seems to like to
render white backgrounds on boxes.
Ref: https://github.com/go-gitea/gitea/issues/3340
Fixes: https://github.com/go-gitea/gitea/issues/12307
* add feature entry, switch to neutral theme, remove border
* add bindFunctions support
* remove unnecessary border-radius
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>
silverwind