JAVA-12045 : move java concurrency ebook content code to common module (#12559)

* JAVA-12045 : move java concurrency ebook content code to common module

* JAVA-12045: addressed the review comments .. renamed package names and placed core-java-concurrency-simple module in pom.xml

* JAVA-12045: removed duplicate module after renaming java-simple-module to core-java-simple-module

core-java-modules/core-java-concurrency-basic/README.md

@@ -3,8 +3,6 @@
 This module contains articles about basic Java concurrency
 
 ### Relevant Articles: 
-- [Guide To CompletableFuture](https://www.baeldung.com/java-completablefuture)
-- [A Guide to the Java ExecutorService](https://www.baeldung.com/java-executor-service-tutorial)
 - [Guide to java.util.concurrent.Future](https://www.baeldung.com/java-future)
 - [Overview of the java.util.concurrent](https://www.baeldung.com/java-util-concurrent)
 - [Implementing a Runnable vs Extending a Thread](https://www.baeldung.com/java-runnable-vs-extending-thread)
@@ -12,5 +10,4 @@ This module contains articles about basic Java concurrency
 - [ExecutorService – Waiting for Threads to Finish](https://www.baeldung.com/java-executor-wait-for-threads)
 - [Runnable vs. Callable in Java](https://www.baeldung.com/java-runnable-callable)
 - [What is Thread-Safety and How to Achieve it?](https://www.baeldung.com/java-thread-safety)
-- [How to Start a Thread in Java](https://www.baeldung.com/java-start-thread)
 - [[Next -->]](/core-java-modules/core-java-concurrency-basic-2)