Include git metadata in docker logs and Google Cloud panic reports

[teor2345]

Motivation

Currently,

• Zebra's Docker logs don't show the git commit
• Zebra's Google Cloud and Docker panic reports only show the git commit, passed through an environmental variable.

But we'd like to see the branch name and other detailed git information via vergen.

The vergen git metadata is likely being disabled because:

• there is no git binary installed in Docker
• there is no .git directory in Google cloud builds, or
• the path to that directory isn't where vergen or the zebrad build script expects it to be.

API Reference

https://docs.rs/vergen/5.1.14/vergen/index.html