Remove Arduino as a language (#3933)

* Remove Arduino as a language

* Move Arduino samples to C++

* Move .ino entry to its correct place

samples/C++/hello.ino

@@ -0,0 +1,7 @@
+void setup() {
+  Serial.begin(9600);
+}
+
+void loop() {
+  Serial.print("Hello");
+}