Add Logs OTLP File exporter

[svetlanabrennan]

Spec says we need to add a File Exporter for Logs.

The spec for the file exporter says it's in "Dev" status so this issue is a placeholder for this work until it becomes stable.

This is not required for Logs GA.

[pichlermarc]

I would like to avoid adding a new experimental package unless we mark a few other ones as stable first, so I'd block this until we have finished the OTLP Exporter GA milestone.

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[github-actions]

This issue was closed because it has been stale for 14 days with no activity.