Added a program sentence_Palindrome.java

[Scarlet-Coder]

The program prints the palindrome words present in the sentence and its frequency.

Pull Request checklist -

• [x] This pull request fixes #2173 2173 (Create an issue if not already present.)
• [x] The directory structure is of the form (directory_name) (If directory doesn't exist, create a new.)
• [x] Don't duplicate stuff.

Make sure all the above conditions are met before a PR is created.