Docker Index docs modified and added to:
move-to-markdown

for Docker Docs' beta release.

Docker-DCO-1.1-Signed-off-by: O.S. Tezer <ostezer@gmail.com> (github: ostezer)
Merge pull request #5017 from ostezer/docs-beta-docker-index-section

Docker Index docs modified and added.
don't use up the port for making a release
make it easier to re-convert or debug the docs with a bind-mount
unicode quotes are so not my friend
update converted docs
Docker Index docs modified and added to:
move-to-markdown

for Docker Docs' beta release.

Docker-DCO-1.1-Signed-off-by: O.S. Tezer <ostezer@gmail.com> (github: ostezer)