docs(ui): add base for ui component showcase in docs (#4414)

platform/docs/pluginOHIFWebpackConfig.js

@@ -21,17 +21,5 @@ module.exports = function (context, options) {
         },
       };
     },
-    configurePostCss(postcssOptions) {
-      postcssOptions.plugins.push(
-        require('postcss-import')
-        /*require('postcss-preset-env')({
-          autoprefixer: {
-            flexbox: 'no-2009',
-          },
-          stage: 4,
-        })*/
-      );
-      return postcssOptions;
-    },
   };
 };