Add palindrome program

[skepttalk]

This PR adds a Palindrome.java program to the Java-Programs repository.

The program takes a string input from the user and checks if it is a palindrome.
It is a beginner-friendly program that helps contributors understand string manipulation in Java.

[IamBisrutPyne]

Hey @skepttalk

This is a great, fundamental pattern for the repository! Palindrome checks are perfect for the SyntaxBasics folder.
As noted in your last PR, administrative files like CONTRIBUTING.md are centrally managed and procedurally-generated. Please remove the CONTRIBUTING.md file from this PR before we can review the code.
Also, the file is missing the required Javadocs-style header block (Title, Author, Date, Description, Time Complexity, and Space Complexity). (Note: This simple solution is $O(N)$ Time and $O(N)$ Space).