[IC3P3]

Refs #276. This covers reload and navigation, not persistence between sessions and clients.

The store's sort and filters are now kept in the URL, so they survive a reload and going back from a game page. Also makes filtered views shareable.

• Adds sort, order, tags, platform and companyActions to the query, while defaults are left out for a cleaner URL
• Invalid values are ignored
• Uses router.replace, so it doesn't add history entries
• Clicking on the header's store link again resets all the filters
• API filter query is now built from the URL filter query, so logic isn't duplicated

Unselecting the tag from the /store/t/[id] isn't saved on a reload, but I think it's not that important, as the page is about this specific tag anyway.

Screenshot