Add Tailwind button for save+cancel

- remove custom styles
- add new button styles based on Tailwind classes using @apply
- extend config to allow hover:ring-blue-200 and such
- update the js-files to use new classes

- Only unsure about the `.review-form .save-non-active`, this might need additional Tailwind helper classes in this specific situation. Don't know where it shows up, so could not test.

tailwind.config.js

@@ -14,7 +14,9 @@ module.exports = {
     },
   },
   variants: {
-    extend: {},
+    extend: {
+      ringColor: ['hover'],
+    }
   },
   plugins: [],
 }