Add checker for html

src/webui/www/.htmlvalidate.json

@@ -0,0 +1,17 @@
+{
+  "extends": [
+    "html-validate:recommended"
+  ],
+  "rules": {
+    "empty-heading": "off",
+    "long-title": "off",
+    "no-conditional-comment": "off",
+    "no-inline-style": "off",
+    "prefer-button": "off",
+    "prefer-tbody": "off",
+    "text-content": "off",
+    "void-style": "off",
+    "wcag/h63": "off",
+    "wcag/h71": "off"
+  }
+}

src/webui/www/package.json

@@ -7,11 +7,12 @@
   },
   "scripts": {
     "format": "js-beautify private/*.html private/scripts/*.js private/views/*.html public/*.html public/scripts/*.js && prettier --write **.css",
-    "lint": "eslint private/*.html private/scripts/*.js private/views/*.html public/*.html public/scripts/*.js && stylelint **/*.css"
+    "lint": "eslint private/*.html private/scripts/*.js private/views/*.html public/*.html public/scripts/*.js && stylelint **/*.css && html-validate private public"
   },
   "devDependencies": {
     "eslint": "*",
     "eslint-plugin-html": "*",
+    "html-validate": "*",
     "js-beautify": "*",
     "prettier": "*",
     "stylelint": "*",