Adjust design of settings page

[straight-shoota]

The implementation of the settings page deviates from the intended design (https://projects.invisionapp.com/d/main?origin=v7#/console/4103589/119909353/preview?scrollOffset=14351). It should be adjusted accordingly.

Current status:

Note: #1550 adds a couple more items and suggests a minor redesign of the page (#1550 (comment)).

[straight-shoota]

A problem with the settings page is that the links to the individual settings pages are implemented via JavaScript event handler, instead of HTML links. Thus you can't do typical link actions such as opening in a new tab. This should be fixed as well.