Add new options to spanmetrics processor in static mode:

[ptodev]

PR Description

Adding new config options to spanmetrics processor in static mode:

• aggregation_temporality: configures whether to reset the metrics after flushing.
• metrics_flush_interval: configures how often to flush generated metrics.

Which issue(s) this PR fixes

Fixes #4614

Notes to the Reviewer

This change is ok from a feature parity point of view because both of these config options are present in otelcol.connector.spanmetrics.

PR Checklist

• CHANGELOG.md updated
• Documentation added
• Tests updated
• Config converters updated

[ptodev]

@tpaschalis thank you for the review, and apologies for the silly errors! Btw I see that we seem to have a practice to list supported values like this:

[ backend: <string> | default = "stdout" | supported = "stdout", "logs_instance" ]

I didn't do this for aggregation_temporality because it'd make the line too long and it looks awkward. But let me know if you feel strongly about it and I'll add this in. There are also a few other places which don't use this syntax to list supported values, so we could add it there too.

[clayton-cornell]

Doc input is minimal. OK as-is.

[tpaschalis]

LGTM, thanks!