This is a comprehensive refactor of visual style using Pico.css framework
as well as extension of functionality to match latest development of
arepo.

Features:

* better visual style using minimalist Pico.css with semantic HTML
* support dark/light themes, resepct browser preference
* smoother page load
* persistent links to projects
* repo selection only shown for projects with multiple repos
* icons for Debian/Ubuntu
* separate data file for all repo data (repos.yaml)
* data import directly from arepo (import_arepo.sh)
* proper repo sorting (by distro and version)
* less intrusive Automated repo setup section (now Accordion)
* added Pin step for Knot DNS