Support pinning paths in the game browser

This is an alternate idea for the same basic functionality of #4390.  I think it's cleaner UI and isn't in the way as much, but is still useful.

It adds a "+" button at the end of directories.  When clicked, the path is now "pinned" and the button changes to "-" (in listing, this is shows as "Pin" and "Unpin".)

When in other directories, these now show up at the top.  It might be ideal to show a pin icon or something...

Also, makes it so you can start extracted isos by browsing, and small tweaks to the game detail screen.

-[Unknown]