We currently hard-code excluding Settings apps from the system menu.
This adds an "ExcludeFromSystemMenu" option to the AppFile configuration
to selectively exclude these apps, which all Settings app now set.
This is to allow selectively excluding a few Demo apps in a future
commit.
This app allows the user to easily adjust his mouse's acceleration
as well as the scrollwheel's global scroll length.
The mouse acceleration changes would not be noticeable in qemu as
by default serenity uses VMWareBackdoor when available which lets
the host handle mouse movement instead of the guest (Serenity),
so in order to test this on a none-baremetal pc the VMWareBackdoor
has to be disabled.
