How to disable API/web endpoints?

How do I disable the API and web components of gitlab ?
While it seems weird, I want to use gitlab as git access control only. So only git commands should be forwarded to gitlab, for example:
git clone example.com/user/repo.git -> goes to gitlab (should work over ssh and http)
http://example.com -> page doesn’t exist (or whatever hosted on example.com)
GET/PUT… example.com/api/v3/users -> page doesn’t exists

Thank you,
Markus

gitlab-shell talks to GitLab via its API, so even if you find a way to disable it will not work at all.