Add the option to run lint and unit test locally.

[ignacio-chiazzo]

The current repository uses a Github Action for running linters Github workflows

Add the option to run the linter locally by running commands. Optionally we can combine unit tests and lint and run them all in one command. There are also a few tests failing that should be updated.

[hot9cups]

As a first step, all the existing lint errors have been fixed, and the failing tests have been updated.
These changes can be found in the following PR - #67

[hot9cups]

I see that

1. EsLint and Tests fix #67 fixed the failing tests and linting errors.
2. Enhancing Tests.js logic #76 has the unit tests enhanced, node Tests.js enables running unit tests locally.
3. Add linter to the README #70 enables running linter and automatic fixing locally via eslint --fix.

Once #76 is merged, I think we should be good to close this issue?

[ignacio-chiazzo]

Thanks for the amazing work on this @hot9cups!