Add recommended VS Code extensions

[robyngit]

To improve collaboration as well as on-boarding of new contributors, we should add a list of recommended VS Code extensions to the repo. This will be particularly helpful in getting developers set up with the tools they need to implement the new linting and formatting guidelines. It seems most of the current contributors are using VS Code, so this is a good place to start.

This is as simple as:

• Creating a .vscode/extensions.json file in the root of the repo.
• Adding extensions to the file in the following format:

{
    "recommendations": [
        "extension.identifier1",
        "extension.identifier2"
    ]
}

Extension IDs can be found by right-clicking on an extension in the Extensions view and selecting "Copy Identifier".

Adding this file will prompt users to install the recommended extensions when they open the repository in VS Code. They can then install them with a single click.

I would propose adding the following extensions to the list:

• Name: ESLint
  Id: dbaeumer.vscode-eslint
  Description: Integrates ESLint JavaScript into VS Code.
  Version: 3.0.10
  Publisher: Microsoft
  VS Marketplace Link: https://marketplace.visualstudio.com/items?itemName=dbaeumer.vscode-eslint

• Name: toggle-eslint
  Id: zentus.toggle-eslint
  Description: Toggle ESLint
  Version: 0.0.3
  Publisher: zentus
  VS Marketplace Link: https://marketplace.visualstudio.com/items?itemName=zentus.toggle-eslint

• Name: Prettier - Code formatter
  Id: esbenp.prettier-vscode
  Description: Code formatter using prettier
  Version: 11.0.0
  Publisher: Prettier
  VS Marketplace Link: https://marketplace.visualstudio.com/items?itemName=esbenp.prettier-vscode

Looking for recommendations on others that would should add @rushirajnenuji @artntek @alonakos @iannesbitt + anyone else!