mediumroast_js: Add duplicate name check on company objects prior to company create

[miha42-github]

Introduction

As we only want to have unique companies a check is required to verify that users do not enter the same name of the company again thus creating a duplicate.

Implementation notes

• This is being accomplished through a simple findByName() call and then a return back to the main CLI.

[miha42-github]

The implementation is completed and has had a basic test, confirmed.