[Feature] Filter by GeforceNow

[mefaba]

As a User I want to be able to filter geforce now games

[arcataroger]

Todo:

• Add "Exclude" filter (when you click the "-" sign to the right, it should only show games that are NOT on GFN). Alternatively, we could hide that icon altogether (why would anyone add this extension only to filter games that aren't on there, lol)
• See whether we can get a more helpful filter count. The previous number was hardcoded. Doing it the "right" way would mean we have to cross-filter all of Steam's results against GFN's entire list, but we don't have access to all of Steam's filtered results (they load dynamically). Maybe we could fake it and just count how many of the currently loaded titles are GFN-compatible, but that would be an invisible difference from the rest of the filters. Probably better to just leave it hidden
• See if we can apply the same sort of filtering to other pages (wishlist, main page, sales, etc.)

[mefaba]

why would anyone add this extension only to filter games that aren't on there.

• Exclude... I havent realized it is there until now. It is not needed in my opinion either.
• We can put the length of the list that we have on data.js. Why do we need to crossfilter entirelist.
• Agree, if pages supporting filtering already, we should add GeForce now filter next to rest.