feature: Add context object pattern (#2304)

* Add context object pattern and corresponding tests

* Update context pattern

* Add README, class diagram, puml file.
Add toString method in ServiceContext.java.
Add tests for coverage.

* Improvements:
Remove plugin in pom file
Add comments in app.java
Change local variable keyword to var in app.java
Use lombok for getters, setters and tostring
Change method signature in context object

* Refreshing environment-1

* Reconfigure pom file.

Co-authored-by: Alvis Chan <u7287079@edu.anu.au>
Co-authored-by: u7287079 <u7287079@anu.edu.au>

context-object/src/test/java/com/iluwatar/contect/object/AppTest.java

@@ -0,0 +1,17 @@
+package com.iluwatar.contect.object;
+
+import com.iluwatar.context.object.App;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+
+public class AppTest {
+
+    /**
+     * Test example app runs without error.
+     */
+    @Test
+    void shouldExecuteWithoutException() {
+        assertDoesNotThrow(() -> App.main(new String[]{}));
+    }
+}