Here we start to have some delicate secrets in the code. Therefore I
need a vault for ansible. This vault contains the tokens to upload
ssh-keys to github and my lovely gitea server.
Note, that this change also adds a `requirements.yml`, this is necessary
because I use the paramater "api_url" of the github_key resource which
was only added in v11, but the debian ansible was shippped with an older
collection.
