Add details for Aggregator in Metrics Spec. (#1842)
Add details for Aggregator in Metrics Spec. (#1842)

* Aggregator Spec

* Cleanup

* Tweaks

* tweaks

* tweak

* Fix up nits from PR feedback

* Fix up nits from PR feedback

* Refactor based on SIG meeting feedback

* Allow idiomatic approach for Aggregator+Params

* Add Timestamp for Last Value Aggregator

* Fix misspelling

* Refactor to use Aggregation (as a config)

* Refactor to use Aggregation (as a config)

* Fix based on PR feedback

* fix misspelling

Co-authored-by: Joshua MacDonald <f3bd74e7fbbcca8170a843c74945d604f45dfc0a@users.noreply.github.com>
open-telemetry/opentelemetry-specification,open-telemetry/opentelemetry-specification