Add mail link to request access for a new user (clavid)

Created by: wasabideveloper

• Show username correct in loggout button for clavid users
• Add a mailto link to send a request access for osmaxx. Include the clavid id into the mail content. In future, this may be replaced by a form.

<a href="mailto:?subject=Request%20access%20for%20osmaxx&body=Clavid%20ID:%20{{ clavidID }}">Request access</a>

Estimated duration: ~0.5d