Improve instructions when the repository is created.

Good day colleagues,

I was moving a bunch of repositories from another GitLab instance (but it does not matter as it could be github, bitbucket, gitea etc.). The customer asked to mirror all the branches and tags. So I spent 5 minutes to find an appropriate commands to do it:

1. git clone --mirror ORIGINAL_URL
2. change the config file of bare git repo to point to NEW_URL
3. git push --mirror
4. repeat the operation for all repos

I would very appreciate if such a help could be shown in empty repo in instructions section. Right now it looks like:

so effectively helping only with case of bootstrapping the new project from the scratch.