Add HTTP/2 gRPC OTLP parsing and tests

[svbergmann]

Summary

• Add HTTP/2 frame parsing with gRPC envelope decoding and OTLP protobuf decoding.
• Extend documentation for OTLP/gRPC over HTTP/2.
• Add unit tests for traces, metrics, trailers, and compressed payload handling.

Changes by file

• doc/user_manual/tigerProxy.adoc: document OTLP/gRPC over HTTP/2 support and limitations.

• tiger-bom/pom.xml: manage newly introduced dependency versions.

• tiger-rbel/pom.xml: add HTTP/2, protobuf, and OpenTelemetry proto dependencies for parsing.

• tiger-rbel/src/main/java/de/gematik/rbellogger/facets/http2/RbelHttp2Converter.java: decode HTTP/2 frames and rebuild stream messages for RBEL.

• tiger-rbel/src/main/java/de/gematik/rbellogger/facets/http2/RbelHttp2MessageFacet.java: model HTTP/2 messages with headers/body/trailers.

• tiger-rbel/src/main/java/de/gematik/rbellogger/facets/grpc/RbelGrpcConverter.java: detect gRPC content types and parse gRPC envelopes.

• tiger-rbel/src/main/java/de/gematik/rbellogger/facets/grpc/RbelGrpcMessageFacet.java: represent gRPC message metadata and frames.

• tiger-rbel/src/main/java/de/gematik/rbellogger/facets/grpc/RbelGrpcFrameFacet.java: represent individual gRPC envelope frames.

• tiger-rbel/src/main/java/de/gematik/rbellogger/facets/otlp/RbelOtlpFacet.java: capture decoded OTLP metadata and payload.

• tiger-rbel/src/main/java/de/gematik/rbellogger/facets/otlp/RbelOtlpGrpcConverter.java: decode OTLP protobuf payloads from gRPC frames.

• tiger-rbel/src/test/java/de/gematik/rbellogger/converter/RbelHttp2GrpcOtlpConverterTest.java: add unit coverage for traces, metrics, trailers, and compressed payload warnings.

  Tests

mvn -pl tiger-rbel -Dtest=RbelHttp2GrpcOtlpConverterTest test