Adding the FAQ back

Docker-DCO-1.1-Signed-off-by: James Turnbull <james@lovedthanlost.net> (github: jamtur01)
Merge pull request #5905 from jamtur01/faq

Adding the FAQ back
Mount /dev in tmpfs for privileged containers
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)