add stylelint-webpack-plugin with stylelint-config-standard and stylelint-scss

Author: hadl

.stylelintrc.json

@@ -0,0 +1,11 @@
+{
+  "extends": "stylelint-config-standard",
+  "plugins": [
+    "stylelint-scss"
+  ],
+  "rules": {
+    "at-rule-no-unknown": null,
+    "scss/at-rule-no-unknown": true,
+    "number-leading-zero": "never"
+  }
+}