Fix a definite style guide, linting fixes, hooks

[YashKumarVerma]

Description

• Important : the diff is auto-generated by eslint & prettier.

What's done in this PR:

• updated old eslint (from v6.8 to v7.x) as 6 is not compatible with prettier plugins
• prettier
  • custom config file to match the code style
  • syncs with eslint to avoid conflicts
• eslint changes
  • configs rewritten
    • removed browser as the backend is not interacting with any browser.
    • added prettier plugin to sync with prettier configs.
  • removes the .eslintignore file as node_modules are skipped by default.
• pre-commit-hooks
  • new dependency
  • runs prettier and eslint-fix automatically before every commit
  • ensures that user always maintain the project code style.
  • option to override the hook if needed.

Motivation and Context

• Fixes #73
• TLDR
  • strict style guide
  • automatically enforced
  • allows us to use automated checks on PR once setup.
  • integration with (almost) all code editors.

How Has This Been Tested?

• [x] the changes are done by an automated tool that changes the style of code. Therefore the code behaves the same way.
• [x] The pre-commit-hooks are manually tested and working.
• [x] The prettier confs and eslint configs are manually tested and do not conflict.

Screenshots (if appropriate)

• NA

Types of changes

**What types of changes does your code introduce? Put an x in all the boxes that apply:

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

Go over all the following points, and put an x in all the boxes that apply. (If you're unsure about any of these, don't hesitate to ask. We're here to help!)

• [x] My code follows the code style of this project.
• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.

I believe that such a big diff and that too generated by an automated tool should be ideally done by the project maintainer, therefore I am converting this PR into a draft PR.