Show a link to the Piwik administration

[tsteur]

It could be nice to maybe show a link "Administration" in the mobile app if the current user has admin permission or super user permission. This would open a link in the browser.

A user asked for this.

Would maybe require an API as it wouldn't be good to hard code the link. At some point we would need an API for top menu items anyway as we want to render everything in the browser.