[JAVA-621] core-java-lang-oop-inheritance module

* Creation

* Moved code from https://www.baeldung.com/java-anonymous-classes

* Moved code from www.baeldung.com/java-polymorphism

* Moved code from www.baeldung.com/java-inheritance

* Moved code from www.baeldung.com/java-variable-method-hiding

* Moved code from https://www.baeldung.com/java-type-casting

* Moved code from https://www.baeldung.com/java-super

* Moved code from www.baeldung.com/java-interfaces

* Moved code from www.baeldung.com/java-abstract-class

* Moved code from www.baeldung.com/java-inner-interfaces

* Moved article references to the new README.md

core-java-modules/core-java-lang-oop/README.md

@@ -4,12 +4,8 @@ This module contains articles about Object-oriented programming (OOP) in Java
 
 ### Relevant Articles: 
 - [Guide to hashCode() in Java](https://www.baeldung.com/java-hashcode)
-- [Polymorphism in Java](https://www.baeldung.com/java-polymorphism)
 - [Method Overloading and Overriding in Java](https://www.baeldung.com/java-method-overload-override)
 - [How to Make a Deep Copy of an Object in Java](https://www.baeldung.com/java-deep-copy)
-- [Guide to Inheritance in Java](https://www.baeldung.com/java-inheritance)
-- [Object Type Casting in Java](https://www.baeldung.com/java-type-casting)
 - [Type Erasure in Java Explained](https://www.baeldung.com/java-type-erasure)
-- [Variable and Method Hiding in Java](https://www.baeldung.com/java-variable-method-hiding)
 - [Object-Oriented-Programming Concepts in Java](https://www.baeldung.com/java-oop)
 - [[More -->]](/core-java-modules/core-java-lang-oop-2)