refactor: Webpack Defaults 2.x merge

[joshwiens]

webpack-defaults 2.x Working branch

• Prettier integration
• CircleCI 2.0 Migration
• Bug fixes from 1.x relating to the Appveyor template
• Dependency Maint
• Supported versions increases
• Add minimal test configuration
• Configure for schema enforcement
• Add CODEOWNERS template

Subject

 refactor: Prettier integration & CircleCI 2.0 migration

Body

refactor: Update node versions for new LTS

 - Updates Node versions to current LTS

BREAKING CHANGE: Drops support for NodeJS 4.x

refactor: Use non-deprecated config type

 - Moves to non-deprecated eslint config  format

refactor: Prettier integration

 - Leverages Prettier to manage code style
 - Migrates to eslint-config-webpack 2.x ( Prettier support)
 - Updates code style per the above
 - Adds `.prettierrc` to enforce development configs

BREAKING CHANGE: Implements Prettier & modifies suported Eslint 
configuration that transfers applicable rule responsibility to Prettier

feat: Adds testing boilerplate
 - Adds contrib standard testing config

feat: Adds schema enforcement
 - Installs schema utils dependency
 - Creates `options.json` template
 - Updates build script to accommodate `options.json`

ci: Migrates to CircleCI 2.0 & custom build containers

 - Migrates to CircleCI & a full continuous delivery workflow

BREAKING CHANGE: Drops TravisCI in favor of CircleCI 2.0

BREAKING CHANGE: Drops support for Webpack 2.x & adds 4.x support

BREAKING CHANGE: Enforces existing commit message format 
in pre-commit as it's required for release automation

Migration 1.x.x => 2.x:

• package.json: Delete all non-project specific devDependencies
• package.json: Delete all npm scripts less "webpack-defaults": "webpack-defaults"
• npm install webpack-defaults@next: Install defaults 2.x
• npm run webpack-defaults: Upgrade to the latest defaults
• .eslintrc: Transfer any custom rules to the rules object in .eslintrc.js after the prettier config array
• .eslintrc: Remove this file
• .travis.yml: Remove this file
• package-lock.json: Delete this file
• npm install: Install updated dependencies & regenerate lock file
• Enable CircleCI 2.0 & import publishing environment variables ( requires an admin )
• Set required validations in project settings
  • Unselect everything but the CLA check & Codecov
  • Select the following CircleCI validations after first run.

Output of defaults beta.0 is visible in webpack-contrib/babel-minify-webpack-plugin#70

[michael-ciniawsky]

Partial Review #86

I will review this later in depth (1-2 days) after I tried it out on a new dummy project (Setup) and on 1-2 current @next PR's e.g html-loader, style-loader, css-loader, [EWTP] (Update/Upgrade) :)