Reenable the Docker pre-commit hooks.

First of all, I'm replacing the hadolint hook that I maintained with the
one from https://github.com/AleksaC/hadolint-py and the docker-compose
hook with the new one I maintain at
https://git.shore.co.il/nimrod/pre-commit-hooks. Both don't require
Docker at all (just regular Python). Also, with
https://github.com/pre-commit/pre-commit/issues/1387 and then
https://github.com/pre-commit/pre-commit/issues/1918 resolved, the
original hooks that required Docker should work anyway.

I'm keeping the gitlab-ci hook disable for now, the 401 issue is still
present and there's little point in validating the CI config while it's
running (it is running after all).