Control if metrics or traces are sent to collector

[ryanrolds]

We currently only want to send metrics to our OTEL Collector. I'm seeing errors about not being able to send traces because the collector doesn't have tracing configured.

This PR adds a flags that allow us to turn off the sending of traces (or metrics if that is your thing).

[mdelapenya]

Before starting the review of this PR, I'd like to put the demos back (elastic, jaeger, etc) to work. I followed the instructions in the readme without success 🤔

[ryanrolds]

Are the issues with the demo related to this PR? I don't think I broke anything. It's fine if they are not, just wanting clarity.

[mdelapenya]

No no, not related at all. Sorry for the confusion. I added that to express that we are adding code with the demos being broken.

[ryanrolds]

In between some tasks, I will go through each of the demos and adjust them.

[mdelapenya]

I'm on PTO until the new year, so will go back to this right after that.

Thank you so much for your work 🙇

[mdelapenya]

LGTM, although I'm missing a test for this, probably because the current state of the code does not allow it.

Can we add a TODO comment, or simply better opening an issue?, so that we can refactor the initialisation of the otel providers and eventually write tests about that?

[mdelapenya]

OR, if you find it testable, e.g. adding multiple instances of the TestMain function with different flags set and expected outcomes, please add it 🙏 I can work on generalise that test function in a separate PR if you see it appropriate

[ryanrolds]

i will see about generalizing things about.