* Deprecate the aggregation pkg
* Decouple the internal/aggregate from aggregation pkg
* Add Aggregation to the metric pkg
* Do not use sdk/metric/aggregation in stdoutmetric exporter
* Update all generated templates
* Update prom exporter
* Fix view example
* Add changes to changelog
* Update CHANGELOG.md
Co-authored-by: Robert Pająk <pellared@hotmail.com>
* Rename Sum to AggregationSum
* Fix comments
* Centralize validation of aggregation in pipeline
* Remove validation of agg in manual_reader selector opt
* Fix merge
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Co-authored-by: Robert Pająk <pellared@hotmail.com>
