fix!: align with the spec for metrics sdk and metrics otlp exporter

[xuan-cao-swi]

Description

1. periodic metrics reader with console exporter default 10s export interval - spec
2. follow the python metrics otlp implementation that shutdown should stop export - py

[mwear]

lgtm, but there are some rubocop failures that need to be addressed.

[simi]

Not sure if related directly to this change, but shouldn't we synchronize shutdown with the export mutex or re-check @shutdown inside the synchronized section? It seems there's lifecycle race now.

[kaylareopelle]

This looks good to me! Do we want any tests to make sure we don't drift away from these changes?

[kaylareopelle]

Not sure if related directly to this change, but shouldn't we synchronize shutdown with the export mutex or re-check @shutdown inside the synchronized section? It seems there's lifecycle race now.

That's a good question, @simi. It might be a separate change to think through. If I'm understanding your question, we don't synchronize shutdown checks in our other exporters. The main OTLP (Traces) exporter doesn't use a mutex at all. I think we should look into this more. If we find a solution, it should be applied to traces, metrics, and logs.