Added proposed Docker Community Guidelines

Docker-DCO-1.1-Signed-off-by: James Turnbull <james@lovedthanlost.net> (github: jamtur01)
Rename DOCKER_CONFIG envvar to DOCKER_CERT_PATH

DOCKER_CONFIG was introduced in #6984.

We may use "config" for other purposes (e.g. #7232). Until we
have made a design decision around how configuration files will
work, DOCKER_CERT_PATH is a much safer name to rely on for future
compatibility.

Docker-DCO-1.1-Signed-off-by: Ben Firshman <ben@firshman.co.uk> (github: bfirsh)
Merge pull request #7412 from bfirsh/rename-docker-config

Rename DOCKER_CONFIG envvar to DOCKER_CERT_PATH
Merge pull request #7186 from jamtur01/community

Added proposed Docker Community Guidelines
Restart containers based on restart policy

Signed-off-by: Michael Crosby <michael@docker.com>
Cleanup restart logic in monitor

Signed-off-by: Michael Crosby <michael@docker.com>
Add typed RestartPolicy

Signed-off-by: Michael Crosby <michael@docker.com>
Refactor container monitor into type

Signed-off-by: Michael Crosby <michael@docker.com>
Add documentation and update restart rules.

Implement time backed backoff for restarting and fix failure count when
the maximum is 0

Signed-off-by: Michael Crosby <michael@docker.com>
Update docs based on feedback from review for --restart

Signed-off-by: Michael Crosby <michael@docker.com>
Only restart containers on daemon load with policy of always

Signed-off-by: Michael Crosby <michael@docker.com>