Continuous profiling for Ruby Projects

This is an attempt to revive #1786 (moved), which was partially implemented in &788. This means that at the time of writing we have profiles for Puma in staging.

This implementation is using a vendored version of remind101/ruby-cloud-profiler which wraps the Google-provided google-cloud-profiler-v2 gem to access the API with stackprof to get samples into the Google Cloud Profiler.

The remind101/ruby-cloud-profiler seems unmaintained, so we might want to fork this ourselves to continue development to integrate the changes and update dependencies.

Ideally, this becomes part of Labkit.

This would help with debugging incidents like production#18538 and production#18535.