Feedback: add support for codeberg

[jmaassen]

We received a request to add codeberg to the list of supported git platforms:

https://codeberg.org/

[ewan-escience]

There are two steps for this:

1. Recognise Codeberg as a Git platform type:
   • add it to the platform_type database enum
   • add it to the frontend, including a logo
2. Add a harvester:
   • programming languages
   • commit history (unclear if in a usable format for us)
   • contributor count
   • star count, fork count, issue count (unclear if we can see if issues are open/closed), there don't seem to be endpoints for the license and whether or not a repo is archived (edit: this gives us all the basic data except license)