refactor(icons): replace FontAwesome with Tabler Icons

Drop the three @fortawesome/* packages (v5, with a stagnant Vue 2
binding) in favor of @tabler/icons-webfont. The old <awe-icon>
wrapper is replaced by <vaquant-icon>, named after the project so
future icon-library swaps don't require another rename.

package.json

@@ -10,9 +10,7 @@
     "build-couch-design": "ts-node src/scripts/validate-doc-update.ts"
   },
   "dependencies": {
-    "@fortawesome/fontawesome-svg-core": "^1.2.28",
-    "@fortawesome/free-solid-svg-icons": "^5.13.0",
-    "@fortawesome/vue-fontawesome": "^0.1.9",
+    "@tabler/icons-webfont": "^3.30.0",
     "@xkeshi/vue-qrcode": "^1.0.0",
     "axios": "^0.19.2",
     "bulma": "^0.8.1",