* Add plugin option for protogen in Makefile
* Fix the generator for the plugin in util/protogen
* Erase convertable types, move helpful methods to gRPC protobufs
* Erase helpers for convertations
* Generate StableMarshlal/StableSize for protobufs by the protoc plugin
Signed-off-by: Airat Arifullin a.arifullin@yadro.com