1. Use general "mobile-only" and "not-mobile" CSS styles, remove some`@media (max-width: 767.98px)` tricks
2. Use `CountFmt` for repo list, just like the repo header (and it matches GitHub, to avoid big numbers bloat the page)
(cherry picked from commit bfa160fc98a23923b6ce1cd4d99e8970d937d6ec)
Conflicts:
templates/explore/repo_list.tmpl
templates/repo/header.tmpl
web_src/css/repo/header.css
Resolved the template conflicts by porting the changes to Forgejo (in
case of `header.tmpl`, applying the changes in `header_fork.tmpl). In
case of the CSS change, opted to take Gitea's version and drop the
entire media query.