Create Joke Service. Closes springframeworkguru#2

src/main/java/vmd/springframework/vmdjokesappv2/services/JokeService.java

@@ -0,0 +1,5 @@
+package vmd.springframework.vmdjokesappv2.services;
+
+public interface JokeService {
+    String getJoke();
+}

src/main/java/vmd/springframework/vmdjokesappv2/services/JokeServiceImpl.java

@@ -0,0 +1,21 @@
+package vmd.springframework.vmdjokesappv2.services;
+
+import guru.springframework.norris.chuck.ChuckNorrisQuotes;
+import org.springframework.stereotype.Service;
+
+@Service
+public class JokeServiceImpl implements JokeService {
+
+    private final ChuckNorrisQuotes chuckNorrisQuotes;
+
+    // Hard-wired. Not DI.
+
+    public JokeServiceImpl() {
+        this.chuckNorrisQuotes = new ChuckNorrisQuotes();
+    }
+
+    @Override
+    public String getJoke() {
+        return chuckNorrisQuotes.getRandomQuote();
+    }
+}