feat: Replace FPO footer-area character flourish with real design element

The footer contains a design flourish of a series of onions, all viewed from various angles, and up until this MR they have been represented in the layout as a series of characters vaguely mimicking the positioning of the onions. This MR replaces them with the proper design element, and accounts for the positioning of this element for all breakpoints.

Closes #27 (closed).