i.e. Make timestamp optional while ingesting histogram data into distribution port - 40,000
so client can ingest histogram data (sample below) - which will use Clock.now()
!M wavefrontHQ#3 1500 wavefrontHQ#10 1000 wavefrontHQ#50 5000 sample.histogram source=test.wavefront.com

* MONIT-26423 - support OTLP Gauge metrics

* MONIT-26424 - Support OTLP Cumulative Sum metrics

* Move test helper out of production code

* MONIT-27039 - Support OTLP Delta Sum metrics

* Add integration tests for delta sums

* MONIT-26428 - Support OTLP Summary metrics

* Preserve existing 'quantile' attributes as '_quantile'

* MONIT-28234 - Set source on OTLP metrics (#7)

Signed-off-by: Sumit Deo <deosu@vmware.com>

* MONIT-26425 - Support OTLP Cumulative Histograms (#8)

* Handle Cumulative Histogram
* Pull out OtlpProtobufPointUtils into separate test class

Co-authored-by: Glenn Oppegard <goppegard@vmware.com>

* Monit 26426 delta histogram (#9)

* Process Delta Histogram

Update OtlpGrpcMetricsHandler's constructor to create new handler for Histogram.
Update OtlpProtobufPointUtils with a logic to process delta histogram.
Fix OtlpHttpHandler to send additional handler for Histogram.
Fix unit tests.

* Fix histogram handler

Update OtlpGrpcMetricsHandler's constructor to initialize histogram handler with a correct HandlerKey.

* Integration test

Add an integration test in OtlpMetricsTest.
Add super() in the constructor of OtlpGrpcMetricsHandler.
Optimize delta histogram processing in OtlpProtobufPointUtils.

* Code coverage

Some optimization in OtlpProtobufPointUtils.
Code coverage.

* Code review

Miscellaneous changes as per PR review.

* [MONIT-27533] Update gRPC and OpenTelemetry dependencies (#10)

- Switch pom to gRPC BOM 1.41.2
- Update opentelemtry dependencies
  - Upgrade to latest jaeger dependency for our jaeger listener
  - Remove alpha BOM that imports a single constant
  - Add new opentelemetry-proto dependency to get exponential histograms

* MONIT-27533: Remove deprecated classes. (#15)

- Change class InstrumentationLibraryMetrics to ScopeMetrics.
- Change class InstrumentationLibrarySpans to ScopeSpans.

* [Monit-28550] Configuration change to not forward resource attributes by default (#17)

* MONIT-28550: Disable forwarding Resource Attributes by default.

- Make changes for both GRPC & http.

* MONIT-26427: Delta + Cumulative Exponential Histogram. (#18)

Also includes MONIT-28482: Cumulative Exponential Histogram.

Co-authored-by: Sumit Deo <deosu@vmware.com>

* Remove a TODO.

* Remove TODO about reporting internal metrics for 400 errors.

Co-authored-by: Peter Stone <stonepe@vmware.com>
Co-authored-by: Peter Stone <thepeterstone@gmail.com>
Co-authored-by: Sumit Deo <93740684+deosu@users.noreply.github.com>
Co-authored-by: keep94 <keep94@gmail.com>
Co-authored-by: Sumit Deo <deosu@vmware.com>
Co-authored-by: Travis Keep <travisk@vmware.com>
Co-authored-by: German Laullon <glaullon@vmware.com>