Pager doesn't work on extensions list

[remicollet]

Example https://packagist.org/extensions?page=2

[naderman]

Looks like the extension controller is missing handling of current page / per page entirely, can probably just copy that over from https://github.com/composer/packagist/blob/1f080cd8e0d896772a830a1c7fb6af3e4c4f65e5/src/Controller/ExploreController.php#L69

[stof]

AFAICT, it currently returns an unpaginated list, so all extensions are returned at once (this is probably not a good idea for scalability)

[stof]

hmm, no. even worse. It loads unpaginated data and then creates a pagerfanta object but without configuring it...

[Seldaek]

This was all quickly glued together PoC code. Good to see more extensions coming, so I guess it's time to clean this up a bit :)

[Seldaek]

Fixed the search as well to search only extensions now when on the extension page.