[Not For Review] Metrics Aggregation SDK

[lalitb]

not to be reviewed Splitting this draft PR into smaller PRs for ease of review.
Fixes # (issue)

Changes

Please provide a brief description of the changes here.

For significant contributions please make sure you have completed the following items:

• CHANGELOG.md updated for non-trivial changes
• Unit tests have been added
• Changes in public API reviewed

[codecov]

Codecov Report

Merging #1173 (62ad88e) into main (1f0bf83) will decrease coverage by 2.60%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##             main    #1173      +/-   ##
==========================================
- Coverage   93.29%   90.70%   -2.59%     
==========================================
  Files         174      185      +11     
  Lines        6391     6587     +196     
==========================================
+ Hits         5962     5974      +12     
- Misses        429      613     +184     

Impacted Files	Coverage Δ
api/include/opentelemetry/common/timestamp.h	90.00% <0.00%> (-10.00%)	⬇️
...pentelemetry/sdk/metrics/aggregator/accumulation.h	0.00% <0.00%> (ø)
...telemetry/sdk/metrics/aggregator/drop_aggregator.h	0.00% <0.00%> (ø)
...etry/sdk/metrics/aggregator/histogram_aggregator.h	0.00% <0.00%> (ø)
...etry/sdk/metrics/aggregator/lastvalue_aggregator.h	0.00% <0.00%> (ø)
...ntelemetry/sdk/metrics/aggregator/sum_aggregator.h	0.00% <0.00%> (ø)
...nclude/opentelemetry/sdk/metrics/data/point_data.h	0.00% <0.00%> (ø)
...clude/opentelemetry/sdk/metrics/view/aggregation.h	100.00% <ø> (+66.67%)	⬆️
sdk/include/opentelemetry/sdk/metrics/view/view.h	63.64% <ø> (ø)
sdk/src/metrics/meter.cc	13.64% <0.00%> (-0.64%)	⬇️
... and 23 more

[lalitb]

Not required anymore.

[lalitb]

Not required anymore.