Upgrade searx

https://github.com/YunoHost-Apps/searx_ynh/pull/9
- Add a license file
- Uses last helpers
- Nginx configuration on one file for subpath and root
- Upgrade 0.11
- Script restore fixed
- Global refactoring

official.json

@@ -93,7 +93,7 @@
     "searx": {
         "branch": "master",
         "level": 3,
-        "revision": "7028ebaf83d53c3c95a95367b568eb44bb6463b6",
+        "revision": "8d0a4f4a9b2874e241cca354208c6afc6804c8a7",
         "state": "validated",
         "url": "https://github.com/YunoHost-Apps/searx_ynh"
     },