Grpc samples cleanup protos

Thanks!

Grpc protos add route guide example service

Added simple overview/quick mention of protocol buffers

Some editing/rewriting of example, fixed links, etc.

grand unified hello world

Remove separate step now that all the content has been moved into the main doc

Remove separate step now that all the content has been moved into the main doc

Remove separate step now that all the content has been moved into the main doc

Remove separate step now everything's been moved into the main doc

Java: move java code to a subdir