⚙ Internal Update

[kurone-kito]

• Added BackstopJS scripts to ignored list of ESLint.
• Migrated some tasks from npm-scripts to Gulp.
  • The npm-scripts are maintained as a façade to Gulp, because it is intended to suppress bloating code of self.
• Refactored and splitted Gulp tasks of already migrated.
• Refactored the config for TypeScript.
• Refactored the config for Webpack.
• Removed the unused some stab for BackstopJS.

Added / Removed dependencies

Type	package	version
devDependencies	@types/through2	2.0.34
devDependencies	@types/vinyl	2.0.2
devDependencies	through2	3.0.1
devDependencies	vinyl	2.2.0
devDependencies	@types/jest	24.0.9 ▶︎ 24.0.11
devDependencies	jest	24.1.0 ▶︎ 24.5.0
devDependencies	shx	(Removed)