[epic] Remove "engine activate/check/update" subcommands

[thaJeztah]

These subcommands were created to allow upgrading a Docker Community engine to Docker Enterprise, but never really took off. With the migration of the docker "enterprise" products to Mirantis, we should remove these subcommands as releases may no longer be done in sync in future.

• Remove "docker engine" subcommands #2207 Remove "docker engine" subcommands
• [master] Remove image-based build (for docker engine activate) docker-ce-packaging#411 Remove image-based build (for docker engine activate)
• [master] Remove some remnants related to image-based builds docker-ce-packaging#420 Remove some remnants related to image-based builds
• Remove more remnants from image-based engine docker-ce-packaging#426 Remove more remnants from image-based engine
• Remove "docker engine" commands docs#9984 Remove "docker engine" commands
• updated deprecated features page (docs: updated "deprecated features" page #2319)
• changes in release-repositories
• backport (packaging changes only?) to 19.03 (and 18.09?) branches

[thaJeztah]

/cc @seemethere (perhaps you know if there's more locations to look for changes to be done?)

/cc @silvin-lubecki

[seemethere]

I believe docker/docker-ce-packaging#411 should suffice

[thaJeztah]

Thanks for looking, @seemethere 🤗

[chris-crone]

@nebuk89 Do we still need to publish the EE images?

[thaJeztah]

Work for this is done for "master" / 20.03, we might still consider backporting to 19.03 packaging, but no need to track that here