feat: gRPC client provider for cross service and external calls #321

Job	Run time
Build and publish artifacts and plugins locally	2m 3s
Basic checks	48s
Check service docker image contents	40s
Run annotation processor tests	1m 6s
Maven samples (shopping-cart-quickstart, true)	44s
Run sbt test	3m 0s
Maven samples (choreography-saga-quickstart, true)	58s
Maven samples (doc-snippets, false)	51s
Maven samples (view-store, true)	1m 11s
Maven samples (spring-dependency-injection, true)	1m 3s
Maven samples (event-sourced-customer-registry, true)	1m 8s
Maven samples (event-sourced-counter-brokers, docker compose up -d, true)	1m 40s
Maven samples (event-sourced-customer-registry-subscriber, true, ./start-upstream.sh)	1m 8s
Maven samples (key-value-counter, true)	41s
Maven samples (key-value-shopping-cart, true)	41s
Maven samples (key-value-customer-registry, true)	54s
Maven samples (tracing, false)	29s
Maven samples (reliable-timers, true)	41s
Maven samples (transfer-workflow, true)	43s
Maven samples (transfer-workflow-compensation, true)	48s
	21m 17s

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