Add a step to verify if Docker is working as expected

Like in the other installation guides I added a simple test
to verify that importing images and starting containers is
working.

Docker-DCO-1.1-Signed-off-by: Christian Berendt <berendt@b1-systems.de> (github: berendt)
use the official  image for now - there's an opensuse image on its way

Docker-DCO-1.1-Signed-off-by: SvenDowideit <SvenDowideit@home.org.au> (github: SvenDowideit)
Add the 1.13 API docs to the menu

Docker-DCO-1.1-Signed-off-by: SvenDowideit <SvenDowideit@home.org.au> (github: SvenDowideit)
Merge pull request #6768 from SvenDowideit/add-1.13-api-to-docs-menu

Add the 1.13 API docs to the menu
Merge pull request #6765 from SvenDowideit/pr_out_use_the_official_image_for_now_there_s_an_opensuse_image_on_its_way

use the official  image for now - there's an opensuse image on its way