Reduce package install size

[domdomegg]

Is your feature request related to a problem? Please describe.

When using this library on products like Google App Engine, all the dependencies are installed as part of deployment: https://cloud.google.com/appengine/docs/standard/nodejs/runtime#dependencies

Currently, almost 80% of our install size is just these libraries and their dependencies. This slows down deployments, and results in warning logs about the package size.

For example:

• @google-cloud/opentelemetry-cloud-monitoring-exporter@0.16.0 is 103MB installed: https://packagephobia.com/result?p=@google-cloud/opentelemetry-cloud-monitoring-exporter@0.16.0
• @google-cloud/opentelemetry-cloud-trace-exporter is 40.6MB installed: https://packagephobia.com/result?p=%40google-cloud%2Fopentelemetry-cloud-trace-exporter

Describe the solution you'd like
Where possible, the number and size of dependencies is cut down so that using these libraries does not negatively affect GAE deployment speed.

Describe alternatives you've considered
Manually bundling and minifying the libraries ourselves. However, this seems likely error prone and adds complexity.

[domdomegg]

Looks like it's mainly from:

• opentelemetry-cloud-monitoring-exporter > googleapis
• opentelemetry-cloud-trace-exporter > google-proto-files

[aabmass]

googleapis

This repo is the main problem, we've seen the issue come up a few times. See #396

There is an alternative library @google-cloud/monitoring that can be used (or we could generate our own stubs) but I don't have time to work on this right now.

Manually bundling and minifying the libraries ourselves. However, this seems likely error prone and adds complexity.

In #396, they used @vercel/ncc to minify the node deps. This works pretty well in my experience.

[aabmass]

• @google-cloud/opentelemetry-cloud-trace-exporter is 40.6MB installed: https://packagephobia.com/result?p=%40google-cloud%2Fopentelemetry-cloud-trace-exporter

Looks like it's mainly from:

• opentelemetry-cloud-trace-exporter > google-proto-files

This was fixed for the trace exporter for #404, released in v2.4.1. Packagephobia now shows 15.3 MB which is mostly @opentelemetry packages