Add Ballerina language (#3818)

* Add Ballerina language

* Add missing file

* Update color

* Update with required changes

* Update sub-module

samples/Ballerina/hello-world-service.bal

@@ -0,0 +1,16 @@
+import ballerina.lang.messages;
+import ballerina.net.http;
+import ballerina.doc;
+
+@doc:Description {value:"By default Ballerina assumes that the service is to be exposed via HTTP/1.1 using the system default port and that all requests coming to the HTTP server will be delivered to this service."}
+service<http> helloWorld {
+    @doc:Description {value:"All resources are invoked with an argument of type message, the built-in reference type representing a network invocation."}
+    resource sayHello (message m) {
+        // Creates an empty message.
+        message response = {};
+        // A util method that can be used to set string payload.
+        messages:setStringPayload(response, "Hello, World!");
+        // Reply keyword sends the response back to the client.
+        reply response;
+    }
+}