Container device add/remove CLI/API documentation RFC

Device add/remove CLI and API documentation.  This is being proposed as
the new API and CLI to see how people like it.

Co-Authored-By: Chris Alfonso <calfonso@redhat.com> (github: calfonso)
Docker-DCO-1.1-Signed-off-by: Ian Main <imain@redhat.com> (github: imain)
"Note that the host device file is required even when removing" might be more clearly stated as "Note that the host device file must exist when you remove the device"