Add support for self-hosted source control

[angrybrad]

I would be nice to add support for self-hosted versions of Github, Gitlab, and Bitbucket.

• https://about.gitlab.com/install/
• https://docs.github.com/en/enterprise-server@3.14/admin/installing-your-enterprise-server
• https://confluence.atlassian.com/bitbucketserver/bitbucket-installation-guide-867338382.html

[holmey]

This would be really great. We would need support for a self-hosted GitLab.
Another way would be a CLI tool capable of pushing the code to the Cloud project like in e.g. Vercel.