Fix security-opt docs

Docker-DCO-1.1-Signed-off-by: Dan Walsh <dwalsh@redhat.com> (github: rhatdan)
Update desktop integration examples to be more up to date.
Chromium > Iceweasel and cool new gparted example.

Docker-DCO-1.1-Signed-off-by: Jessica Frazelle <jess@docker.com> (github: jfrazelle)
Merge pull request #8496 from jfrazelle/update-desktop-examples

Update desktop integration examples to be more awesome.
Merge pull request #8384 from rhatdan/selinux-opts

Fix security-opt docs