Merge pull request #2954 from tbetbetbe/grpc-ruby-mv-interop-test-to-pb

src/ruby/.rubocop.yml

src/ruby/bin/grpc_ruby_interop_client

src/ruby/bin/grpc_ruby_interop_server

src/ruby/bin/interop/README.md

src/ruby/bin/interop/interop_client.rb

src/ruby/bin/interop/interop_server.rb

src/ruby/bin/interop/test/cpp/interop/empty.rb

src/ruby/grpc.gemspec

src/ruby/pb/README.md

src/ruby/pb/test/client.rb

src/ruby/pb/test/proto/empty.rb

src/ruby/pb/test/proto/messages.rb

src/ruby/pb/test/proto/test.rb

src/ruby/pb/test/proto/test_services.rb

src/ruby/pb/test/server.rb

src/ruby/spec/pb/health/checker_spec.rb