Move bottom navigation bar to different location

[marcodamm]

I have noticed that the dual top navigation bars and the fixed bottom navigation bar take up quite a lot of vertical screen estate.

I already consolidated the top two navbars into a single navigation element (see my PR #56 and the attached screenshot) and in order to save vertical screen estate I would like to suggest to move the bottom navigation bar including the copyright notice to a different location. Solutions could be:

1. Moving the copyright notice to a separate page
2. Making the positioning of the bottom bar relative instead of fixed so it will only be visible when actually scrolling to the bottom of the page.

If we can agree on a solution I can prepare a pull request accordingly.