core: Adding testing framework

## Introduction of testing framework

**Describe the solution you'd like**
Integrating a testing framework, such as Mocha, into Universal-Box. This will allow contributors to write and execute tests for their features, ensuring that all changes are validated before being merged. The testing framework should be set up to run tests automatically during CI workflows, enhancing code quality and reliability.

- will allow developers to test their changes locally before pushing them, reducing the likelihood of introducing bugs into the main codebase.
- automated tests will facilitate continuous integration workflows, ensuring that all code changes are validated against existing functionality

**Expectations: **
- Creation of a `tests/` directory in the root level and writing corresponding test scripts for every `bin/` scripts
- Include npm command preferably `npm test` and `npm test --watch` in `package.json`
- Configure Github actions in such a manner that everytime a push happens to the `bin/` directory the tests will run coz other pushes like templates and docs improvements dosen't affect the package level code

Look at the existing bin/ scripts to understand their functionality. Set up Mocha in package.json with test and test:watch scripts. Create a tests/ directory and write test scripts for each bin/ script. Configure GitHub Actions to run tests on pushes to the bin/ directory. Verify the setup by running npm test locally.

索引モデルが issue の本文から書いたものです。