Writing the results of failed and successful validation functions to a JSON file

[viktorpm]

At the moment, the results (lists, dictionaries of lists) are printed in the console. While this was initially a good solution for testing the functions, it has become challenging to read and follow. After a discussion with @alessandrofelder, we have decided to enhance the clarity by storing cleaner results in a JSON file. This approach will prove valuable later, especially for a potential atlas validation Napari plugin.

PR related to the issue: #115