initializate client, server, shared

- initializated base structure of server
 - initializated base structure of client
 - initializated base structure of shared(lib for client and server)

server/bin/server.dart

@@ -0,0 +1,5 @@
+import 'package:server/server.dart' as server;
+
+void main(List<String> arguments) {
+  print('Hello world: ${server.calculate()}!');
+}