Disable asset pipeline logging messages (2)

Apparently the configuration change did not work out as intended.
Instead I am now using a gem to mute the asset pipeline logger.

Signed-off-by: Konrad Reiche <konrad.reiche@gmail.com>
Start to style dashboard for metrics overview

I have added CSS rules for styling the dashboard for the metrics
overview. I am planing to use this dashboard for following pages,
too. The dashboard will be the main content of a page.

Signed-off-by: Konrad Reiche <konrad.reiche@gmail.com>