webpack explicit path could be omitted from "build" and "start" scripts under package.json file

To work across all platforms including **windows**, explicit path of webpack could be omitted as NPM handles this automatically. With explicit path getting error **_"'node_modules' is not recognized as an internal or external command" on Windows machine_**.

From:
"build": "node_modules/.bin/webpack --config webpack.config.js",
"start": "node_modules/.bin/webpack serve --config webpack.config.js --open"

To:
"build": "webpack --config webpack.config.js",
"start": "webpack serve --config webpack.config.js --open"