feat(nodejs): add ability to be able to enable/disable active instrumentations by env var

[serkan-ozal]

No description provided.

[RaphaelManke]

I like the idea to give more control of what is loaded and what not.

This change seems to introduce a configuration option (unless it's just something experimental/internal right now) and therefore should have a documentation section in the readme.

[serkan-ozal]

These configurations are already in use ones as mentioned here: https://opentelemetry.io/docs/zero-code/js/configuration/#excluding-instrumentation-libraries

[tylerbenson]

It looks like Node already follows this convention, so that's fine. Just pointing it out that Java does it a bit differently: https://opentelemetry.io/docs/zero-code/java/agent/disable/#enable-only-specific-instrumentation

[tylerbenson]

looks ok to me.