Adding first draft of Official Repo Guidelines

Docker-DCO-1.1-Signed-off-by: Fred Lifton <fred.lifton@docker.com> (github: fredlf)
Revisions based on feedback.

Docker-DCO-1.1-Signed-off-by: Fred Lifton <fred.lifton@docker.com> (github: fredlf)
Format and typo fixes

Docker-DCO-1.1-Signed-off-by: Fred Lifton <fred.lifton@docker.com> (github: fredlf)
More format fixes.

Docker-DCO-1.1-Signed-off-by: Fred Lifton <fred.lifton@docker.com> (github: fredlf)
More format wrestling.

Docker-DCO-1.1-Signed-off-by: Fred Lifton <fred.lifton@docker.com> (github: fredlf)
Fix formatting, change to markdown block for long

Signed-off-by: Joe Ferguson <joe@infosiftr.com>
Merge pull request #1 from yosifkit/adding_official-repo-guidelines

Fix formatting, change to markdown block for long
Fixes a couple small typos

Docker-DCO-1.1-Signed-off-by: Fred Lifton <fred.lifton@docker.com> (github: fredlf)
Merge branch 'adding_official-repo-guidelines' of https://github.com/fredlf/docker into adding_official-repo-guidelines

Conflicts:
	docs/sources/docker-hub/official_repos.md

Docker-DCO-1.1-Signed-off-by: Fred Lifton <fred.lifton@docker.com> (github: fredlf)
Adding new Dockerfile Best Practices doc, and links thereto.

Docker-DCO-1.1-Signed-off-by: Fred Lifton <fred.lifton@docker.com> (github: fredlf)
Typo and formatting fixes. Copy edits.

Docker-DCO-1.1-Signed-off-by: Fred Lifton <fred.lifton@docker.com> (github: fredlf)
Revisions and edits based on feedback.

Docker-DCO-1.1-Signed-off-by: Fred Lifton <fred.lifton@docker.com> (github: fredlf)
Merge pull request #8197 from fredlf/adding_official-repo-guidelines

Docs for Official Repo release