Move default configuration template generation out of settings.py

[dmsimard]

The configuration template is currently created out of settings.py: https://github.com/ansible-community/ara/blob/d56c68f749476e761d7d62a60c6d8843b95bf5eb/ara/server/settings.py#L202-L234

This feature is useful but would be better suited as a CLI command so, amongst other things, it doesn't run every time settings.py is loaded.