feature/read functionality

[r-el]

• Add readAll method
• Add read(id, callback) method
• Add test for read and readAll methods
• Fix constructor test to validate file path correctly
• Update test scripts to run both basic and read tests
• Add test-read.js test file
• Add basic tests for JsonFileCRUD constructor and methods [RENAME test.js to test-basic.js]
• Update test scripts to reference the correct test files
• Refactor JsonFileCRUD class structure by organizing methods into regions and removing the unused read method
• Replace 'read' method to 'findById' method in required methods test
• Add Test for findById method
• Add findBy method for filtering items by custom callback
• Add test for 'findBy' method
• Add count(callback) method
• Add test for count method