debt: remove unmaintained tracing code

[mastercactapus]

Tracing code was added with spans for debugging things like GraphQL & DB calls that we have other tools for now. This code hasn't been maintained for a long time and just adds noise, complexity, and build time.

We should pull it out and remove the dependencies:

• cloud.google.com/go
• contrib.go.opencensus.io/exporter/jaeger
• contrib.go.opencensus.io/exporter/stackdriver
• go.opencensus.io

---

If requested we can re-introduce it in the future in a planned and maintainable way.

[alishahwee]

Hey, could I take this on?

[mastercactapus]

@alishahwee Absolutely! It will touch a lot of files, so feel free to break it into pieces/multiple PRs if you run into tricky bits.