main: Move header to footer, page heading to header

Previous version

Before (👎)	After (👍)

Please use 👎, 👍 to show your preference for the change.

This MR moves the current header with navigation buttons and the page number to the footer, and the header instead has the page's title/heading.

Welcome page	View of layers	Layers in KCM

Votes via reactions were for a previous version of the MR, preserved above.