Add exceptionmetricsprocessor

[marctc]

Description: Added processor to create metrics from recorded exceptions. The implementation
is heavily inspired from spanmetricsprocessor.

Link to tracking Issue: #17272

Note for reviewers: Does it make sense to reuse some of the functions from spanmetricsprocessor that
are duplicated here? Or would it be better to do some refactorings and extract common files/functions in a separate
directory?

Documentation: Added examples in README.

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: marctc / name: Marc Tudurí (be11437, a7b989e, 09493c5, 606afb9, f456fd2, c17d58f, 2cd29b8, 18bdd78, 50570a9, 3e23d41, b2c7106)

[djaglowski]

@marctc, thanks for the contribution.

Please read through the guidelines for contributing a component. The most important point is that you'll need to open an issue to propose the component, with the goal of finding a "sponsor" (a maintainer or approver who is willing to co-own the component).

For what it's worth, I think a component like this makes sense, but we will probably want it implemented as a "connector". (See open-telemetry/opentelemetry-collector#6700)

[marctc]

@djaglowski thanks for the info! I created the issue here: #17272. I'm reading the contributing guidelines for the mising steps.

[github-actions]

This PR was marked stale due to lack of activity. It will be closed in 14 days.

[github-actions]

Closed as inactive. Feel free to reopen if this PR is still being worked on.