Docker CLI should use mount API for --tmpfs

This is a follow-up to https://github.com/moby/moby/pull/35467#issuecomment-345036525

The --tmpfs option adds tmpfs mounts to a container. This option is currently handled daemon-side, where mounts specified through --tmpfs are merged with the default mounts, mounts from -v / --volume, and mounts specified through --mount.

We should change the CLI to use the Mount API

• The mount API was added in API 1.25 (Docker 1.13), added through https://github.com/moby/moby/pull/22373, https://github.com/moby/moby/pull/26837, so can be used on any supported version of Docker (both CE and EE). For older daemons/API versions, the CLI should still use the old options.
• Effectively, --tmpfs becomes an "alias" for --mount type=tmpfs ....

Question

• Should we do the same for --shm-size?
• If we do; where are the defaults set? i.e., we likely don't want the CLI to be aware of any defaults set by the daemon for /dev/shm; how can we provide a custom --shm-size, but keep other defaults as-is?

ping @kolyshkin @cpuguy83 @AkihiroSuda PTAL

Start with the Docker CLI handling for --tmpfs, the Mount API version-history entry for API 1.25, and the referenced pull requests. Define how --tmpfs maps to --mount type=tmpfs while preserving the fallback for older daemons; resolve whether --shm-size belongs in the same change and how daemon defaults remain intact.