Add hostname and ID docker info

replace #9126 

This PR add the Hostname to `docker info`; it's the machine hostname, so it might not be unique.
This PR also add the ID of the engine to `docker info`; this ID is generated using libTrust, it is unique.

I extracted some code from #8265
can we say `a hostname (`Name`)` - so it won't be confused with some other 'name'