Is your feature request related to a problem? Please describe.

• The code in bin is not well managed by tools like eslint, babel or other tools
• The code has not been covered by any of the tests so far

Describe the solution you'd like

1. move all code from bin into src
2. rename htmlhint into cli.js
3. create a file bin/htmlhint.js, this file requires the src/cli.js
4. fix bin in package.json
5. fix broken require statements in files

Additional context
I have already tested that in https://github.com/Shinigami92/HTMLHint/tree/structure/move-bin
But the changes are already outdated
I will create a PR when the time is right