move clipboard.js to npm/webpack (#10183)

- created lazy-loaded webpack chunk for clipboard.js
- upgraded clipboard.js from 1.5.9 to 2.0.4
- parallelize initialization of all lazy-loaded features

Co-authored-by: Antoine GIRARD <sapk@users.noreply.github.com>

package.json

@@ -5,6 +5,7 @@
     "node": ">=10"
   },
   "dependencies": {
+    "clipboard": "2.0.4",
     "fomantic-ui": "2.8.3",
     "highlight.js": "9.18.1",
     "jquery": "3.4.1",