DaprController.java as a non-springboot controller

Could we make this a non-springboot controller in case we want to use the Actor SDK without springboot? Also, can we have this available as a gRPC endpoint at some point?

https://github.com/dapr/java-sdk/blob/master/sdk-springboot/src/main/java/io/dapr/springboot/DaprController.java

Start by reading sdk-springboot/src/main/java/io/dapr/springboot/DaprController.java and determine which behavior depends on Spring Boot. The issue also asks for a gRPC endpoint, but gives no design, entry point, or tests; clarify whether these are one change or separate work and define acceptance criteria before implementation.

Written by the indexing model from the issue text.