Hide user settings form if not logged in.
Instead we show a message that you need to log in.

Change-Id: I9861458474c47019ff6714fdadb90f80aae8b96d
Added admin page where you can add users.
Adding a user just adds them to the user settings database so they get emails.
Added unsubscribe link to email notifications.

Change-Id: I604e11fe8ba863a7b7f23502ce4396abc9dca4f1
Move jwt signature key to config file.

Change-Id: Id51de468ef5dd9444549b5d1524b9d1eff1cbcf8
Use express request header instead of decoding json token.

Change-Id: I11ac66bd27e4e71356066dac78199b02dc1a6edc