Add testing workflow for C++ tests

[smokestacklightnin]

This PR adds a workflow that runs C++ tests using Bazel to run gtest.

There are currently build failures in some of the proto modules that prevent the tests from being run.

It's also worth noting that the tests take more than five hours to build on the GitHub runners.

Tests pass locally for me, but won't run on GitHub Actions until the build errors disappear.