feat: move reference extraction into an external lib

Author: rmelisson

package.json

@@ -34,6 +34,7 @@
     "@socialgouv/cdtn-slugify": "^4.44.0",
     "@socialgouv/eslint-config-recommended": "^1.46.0",
     "@socialgouv/legi-data": "^2.45.0",
+    "@socialgouv/reference-article": "^1.0.1",
     "babel-jest": "^26.6.3",
     "eslint": "^7.17.0",
     "esm": "^3.2.25",
@@ -48,7 +49,7 @@
     "superagent": "^6.1.0",
     "talisman": "^1.1.4",
     "unist-util-find": "^1.0.2",
-    "unist-util-visit": "^2.0.3"
+    "unist-util-visit": "^2.0.3",
   },
   "jest": {
     "roots": [