Add ability to create ssh-keys and provide it to github and gitea

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.

ansible.cfg

@@ -5,3 +5,4 @@ become = True
 ask-become-pass = True
 display_skipped_hosts = False
 error_on_undefined_vars = True
+vault_password_file = password.txt