config(8) - remove 'device'

hello,

as older BSD users may remember, 'device' when used in a kernel config
used to have a fairly specific syntax, e.g.:

device foo0 at pci? irq? ... etc ...

nowdays of course this isn't a thing, you just write:

device foo

so, practically this is no different from writing:

options FOO

i propose to remove the 'device' syntax from config(8) and simply use
'options' to include various parts of kernel code in the kernel.

i am prepared to create a patch to do this, but of course, i would
prefer to find out if people would accept this before putting the effort
in.

the concrete benefit of this is that we don't have two different
syntaxes in kernel configs that do exactly the same thing.