[Core] Create an app to manage data encryption

[michalbabiarz]

User story:
As a MC user I want to have an tool to easily encrypt/decrypt sensitive data.

Acceptance criteria:

1. Create DateEncryptionServiceApp in src/main/java/com/capgemini/mrchecker/test/core/utils/.
2. Use Swing for a UI.
3. The app should encrypt/decrypt data.
4. It should use secretData file ref or direct key input.
5. Separate GUI from Business logic (e.g. MVC pattern).
6. Cover business logic with JUnits.
7. Take care of exception handling.
8. It should be run from a jar file giving the right main class (create a .bat file).
9. Create an brief instruction how to run it.