Fix Docker Hub tags list specification

The current implementation of the Docker Hub returns a list of objects
containing the tag name and the layer id.

Docker-DCO-1.1-Signed-off-by: Vincent Giersch <vincent.giersch@ovh.net>
Fix typo in Docker Links chapter of User Guide
Fix mkdir typo in dockerfile_best-practices.md.
Merge pull request #9029 from ovh/fix/doc

Fix Docker Hub tags list specification
Merge pull request #9057 from andi5/typo-best-practices

Fix mkdir typo in dockerfile_best-practices.md.
Merge pull request #9052 from andreyst/master

Fix typo in Docker Links chapter of User Guide