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.
The group_vars dir is the standard destination for ansible to look for
variable-files. So I do not have to declare them in the main.yml
anymore. This change will make it easier for me to reason about upcoming
changes, like using a vault for sensitive information.
