Provide more themes selection by default

[uvulpos]

Feature Description

When you run Gitea as Docker Container or Kubernetes without mounting the public folder to the host, it gets hacky when you want to install a custom theme. To prevent this, I could imagine that Gitea gives you an option to download and provide a Theme. I could now imagine two ways how it could be provided:

1. You define a gitea.theme.yaml that an external git server has to provide and gives you all the information you need to register a theme. This would also include an option to version migrate it (maybe SHA git hash?)
2. You create an Option, that System Administrator can CRUD Upload a CSS File and manage it that way.

What do you think about that idea?

List of awesome Themes: https://gitea.com/gitea/awesome-gitea#themes

Screenshots

No response

[lunny]

I like the first idea.