Clean up stylesheets and remove content rule

I have removed the custom stylesheet. Styles that should be applied on
every page belong, to my mind, into the application stylesheet. Also got
rid of the content rule. Rather than defining the first div element on a
page as "content start" I migrate the stylings into h2, which is always
there.

Signed-off-by: Konrad Reiche <konrad.reiche@gmail.com>
Delete deprecated metric detail views

Just got rid of a lot of deprecated code that I do not need any longer.
If I want to look up how I implemented certain things I can take a look
into the git history.

Signed-off-by: Konrad Reiche <konrad.reiche@gmail.com>
Separate tab selector into its own dashboard

The tabs of the metric report did not seem to integrate very well with
the current design. Hence, I have changed them to navigation pills and
moved the selection into a separate dashboard.

Signed-off-by: Konrad Reiche <konrad.reiche@gmail.com>
Declare metric fields explicitly for record class

In order to enable a method access and indifferent hash access I am
declaring the metric fields now explicitly.

Signed-off-by: Konrad Reiche <konrad.reiche@gmail.com>
Rename default partial to generic partial

The previously named default partial to generate a metric report for
every metric is rather a generic report than a default one.

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