Stats/Settings QoL Improvements + TTU Fixes

Various quality of life improvements, with a focus on the stats page, settings and TTU support:

• Filter stats by type (VNs, LNs, Manga or All)
• Settings page (EDIT: added button to link to it from the main VN page)
• TTU tracking mostly works, but with some minor visual glitches (refresh page to fix)
• Manga series (usually the folder name, which should most of the time be the series title) identifier is displayed instead of the full json
• Mokuro's default AFK pause time has been increased to 120 second
• Mokuro defaults to single page mode
• Extension installs refresh all pages fixed, so weird duping doesn't occur