Switch to vertx-grpc-client

As today, the vertx-grpc library is still based on grpc-java which has a number of issues and given the time I have to maintain the project, it make maintenance harder hence, given the project is already vert.x based, wet should switch to the [vert.x grpc client](https://vertx.io/docs/vertx-grpc/java/#_vert_x_grpc_client)

- https://github.com/etcd-io/jetcd/issues/1370
- https://vertx.io/docs/vertx-grpc/java/#_vert_x_grpc_client
- https://github.com/eclipse-vertx/vertx-service-resolver
- https://github.com/eclipse-vertx/vertx-grpc/issues/100
- https://github.com/eclipse-vertx/vert.x/blob/master/src/main/java/examples/HTTPExamples.java#L1405
- https://github.com/eclipse-vertx/vertx-grpc/blob/main/vertx-grpc-client/src/main/java/io/vertx/grpc/client/GrpcClient.java#L95