Support gitea/forgejo

**Is your feature request related to a problem? Please describe.**
Currently, the CLI only supports repositories hosted on GitHub and GitLab. Many of us primarily use Gitea/Forgejo-based git servers, and I think it would be nice for the CLI to support repositories hosted on them.

**Describe the solution you'd like**
Add support for fetching user information and contributor data from Gitea/Forgejo using its API.

**Describe alternatives you've considered**
To my knowledge, there is currently no functional workaround.

**Additional context**
You can fetch a user on a Gitea server by their username using the `/users/{username}` endpoint ([swagger](https://gitea.com/api/swagger#/user/userGet))

Gitea does not explicitly have an endpoint to list all contributors of a repository, however, you can get a paginated list of all commits using the `/repos/{owner}/{repo}/commits` endpoint ([swagger](https://gitea.com/api/swagger#/repository/repoGetAllCommits)). Perhaps we could fetch all the pages and find all the collaborators using that?

The Forgejo API mirrors that of Gitea.