Proposal: Container device add/remove CLI/API documentation

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)
This is the format that 'ParseDevice' expects so it's actually easier to pass it in as the string.  We could break it up though if that makes more sense long term.  Right now we're relying on the format matching the internal parsing.