* Add --vm-id to wslinfo usage string
* Pass the VM id to init
This change ensures that we pass the vm id to an
instances init. The id is then set as an environment
variable and can be accessed at runtime.
* Expose VM id to wslinfo
Add a new argument --vm-id to wslinfo so that
the caller can retrieve the VM id by calling the
binary.
Although it is an environment variable, it can be useful
here too to save additional string parsing from the caller.