Public Changes -
* Add a pkgconfig installer for `grpcpp_otel_plugin`
Example Changes -
* Add example of how to use the pkgconfig for `grpcpp_otel_plugin` with the existing OpenTelemetry example.
* Add another OpenTelemetry example that uses OTel's OStream exporter. This makes it easier to test the pkgconfig file for `grpcpp_otel_plugin` since the OStream exporter does not require any additional dependencies, as opposed to the Prometheus exporter.
Test changes -
* Modify `run_distrib_test_cmake_pkgconfig.sh` test to install opentelemetry and build the example with the OStream exporter.
Closes#36686
PiperOrigin-RevId: 636965475
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1. All greeter servers now support flag `--port` to customize the listen
port.
2. All client implementation now have `--target` flag to specify the
server location.
3. ABSL is used to parse the flags to reduce the amount of boilerplate
code in the examples.
Fixes: #26989
* De-experimentalize callback API
* Make FromServerContext based on ServerContextBase
* Fix lambda
* Fix headers
* De-experimentalize tests
* clang-format
* Fix consistency checks
* wip
* Fix const-ness of callback client read RPC requests
* Fix golden file
* Give full route_guide callback client example with Hold etc
* Complete example route-guide server
* De-experimentalize test services
* Omit unneeded using
* Remove some uses of non-experimental macro from test
* clang-format examples
* De-experimentalize async stub calls
* Remove experimental namespace use in qps, ubms
* De-experimentalize alarms, generic stubs, and context allocator
* De-experimentalize SetContextAllocator
* clang-format
* Fix conflicts
* Leave obsolete API in place until users can be migrated
-) Fixing Bazel 0.4.x breakage
-) Adding helloworld BUILD examples
-) Fixing grpc++ missing files.
-) Adding helloworld example as a test for Bazel basic.