Add faux-mgs binary to the switch zone

[jgallagher]

Closes #6153

[leftwo]

This does not require any other changes to land in the switch zone?
To get the things I wanted into the global zone I had to update dev-tools/releng/src/main.rs
but, perhaps things are different for the switch zone?

[jgallagher]

This does not require any other changes to land in the switch zone? To get the things I wanted into the global zone I had to update dev-tools/releng/src/main.rs but, perhaps things are different for the switch zone?

Nope, just this. The key line for the switch zone is this one - by adding the omicron-faux-mgs zone tarball to the list of packages for the composite switch zone package, its files get dropped in too.