fix(template): Change initial GitLab-CE root password information

[ChrLau]

Previous mentioned URL https://docs.gitlab.com/omnibus/docker/README.html#after-starting-a-container is now 404.

The command on how to get the initial root password is from the following chapter: https://docs.gitlab.com/ee/install/docker.html#install-gitlab-using-docker-engine

Sadly there is no anchor to link directly to the command. Hence I opted for mentioning it directly in the notes.