Move files from Frontend directory to pcsx2 and/or subdirectories.
Get rid of double GS init.
Combine HostSettings and Host.
Combine Frontend/Achievements.h and Achievements.h.
In reality it will show multiple flags like Korean flag but the flags aren't correct due to the structure in the GameDB actually being the languages more than the actual region.
At least people will have Korean flags and others for now and fix GameDB later as it's still a nightly/development cycle.
Though there are about 30 country flags included for future usage as of now.
Upscaling on Qt didn't work properly as Windows calculates it differently, it's better to give far larger pictures and icons and let it downscale.
Also added most country flags that are relevant for PCSX2.
Reduces size icons from 3.5 MB to a whopping 0.34 MB (340 KB!) but looks even better for everyone.
Hopefully fixes#6255
