Allow sharing UTS namespace of another container

[Rid]

Signed-off-by: Grant Millar [email protected]

- What I did Allow sharing of the UTS namespace of another container using --uts container:<name|id>

- How I did it

• Updated tests
• Updated bash/fish shell completion
• Updated readme

- How to verify it See https://github.com/moby/moby/pull/43349

- Description for the changelog

Allow sharing UTS namespace of another container

- A picture of a cute animal (not mandatory but encouraged) 🐤

This first requires vendoring of https://github.com/moby/moby/pull/43349 due to changes in host_config interfaces.