Add setting global default overclock

[espensa]

One feature I miss from PSVShell is being able to set a global default overclock, as I'd rather set one for all apps (battery life is of no concern), and set exceptions for any that I don't want to use the default settings on.

[Husky363]

i was about to make a post about this feature . i wish if its possible to add a global default clock settings would be good . thats the only reason i havent upgraded from psvshell to the one that is made by GrapheneCt