Split Node examples into static and dynamic code generation examples

examples/node/README.md

examples/node/dynamic_codegen/README.md

examples/node/dynamic_codegen/greeter_client.js

examples/node/dynamic_codegen/greeter_server.js

examples/node/dynamic_codegen/route_guide/README.md

...es/node/dynamic_codegen/route_guide/route_guide_client.js

...ples/node/dynamic_codegen/route_guide/route_guide_db.json

...es/node/dynamic_codegen/route_guide/route_guide_server.js

examples/node/package.json

examples/node/static_codegen/README.md

examples/node/static_codegen/greeter_client.js

examples/node/static_codegen/greeter_server.js

examples/node/static_codegen/helloworld_grpc_pb.js

examples/node/static_codegen/helloworld_pb.js

examples/node/static_codegen/route_guide/README.md

...les/node/static_codegen/route_guide/route_guide_client.js

examples/node/static_codegen/route_guide/route_guide_db.json

...es/node/static_codegen/route_guide/route_guide_grpc_pb.js

examples/node/static_codegen/route_guide/route_guide_pb.js

...les/node/static_codegen/route_guide/route_guide_server.js