Support `router-api` annotations for gRPC services #912
gRPC should support annotations that help to configure the execution
gRPC routes correctly compute per-route execution strategy
Motivation: gRPC should support annotations that help to configure the execution strategy per service or per route. Also, gRPC should compute the effective execution strategy based on the main execution strategy from the builder configuration and from the route configuration. Modifications: - Parse annotations from `route-api` module; - Compute difference between execution strategy on the builder and on the route; - Add tests to verify that offloading works correctly for different execution strategy configurations; - Add tests to verify that misconfiguration of `route-api` annotations will be explained to the user; - Adjust gRPC codegen for new features; - Fix tests; Result: gRPC routes correctly support per-route execution strategy configuration.