hidraw(4): Add HIDRAW_MAKE_UHID_ALIAS kernel option

which installs /dev/uhid# alias to hidraw character device for
compatibility with some existing uhid(4) users like Firefox.
As side effect it renames traditional uhid(4) driver to hidraw
to make possible using of common unit number allocator.

Requested by: Greg V <greg_unrelenting.technology>
Reviewed by: hselasky (as part of D27992)