This is a problem that's bugged me for a long time - it's good to see people working on it. Deploying and managing most traditional CMSes is a nightmare, IMO.
MODX has had something similar for a while with Gitify[1] for the site structure and VersionX[2] for content, but I haven't had much of a chance to use them.
[1] https://github.com/modmore/Gitify [2] https://modx.com/extras/package/versionx