Support default password encrypt with ansible vault

[lokori]

It would be nice if the password files could be encrypted with Ansible vault. Recent versions of Ansible support Ansible vault encryption for copy tasks so this might not require any actual changes, or very minimal changes.

For encrypted files, copy task requires the vault-password from a file, given in a command line parameter. Playbook can't apparently required prompt for password during installation.

[noidi]

The password files should not be commited at all (they contain the default passwords for new users and the users can and should change them). I'd rather create a .gitignore file in the password directory to prevent accidental commits of plaintext passwords.