refactor(storybook): storybook enhancement and cleanup

refactored the storybook codebase for all components

re #381

story/inputs/input.template.js

@@ -0,0 +1,20 @@
+import { select } from '@storybook/addon-knobs';
+import classNames from 'classnames';
+
+import sharedOptions from '../_helpers/shared';
+
+export default () => {
+  const inputOptions = select('Input Classes', {
+    default: '',
+    ...sharedOptions,
+  }, '');
+
+  const inputClasses = classNames(
+    'nes-input',
+    inputOptions,
+  );
+
+  return `
+    <input type="text" id="name_field" class="${inputClasses}" placeholder="NES.css">
+  `;
+};