Add dbOwner role for _restore database to mongo-init.sh script

When restoring an installation from backup, the unifi network application tries to drop the `${MONGODB_DBNAME}_restore` database, which fails because the user used to authenticate with MonboDB doesn't have the permissions to do so.

Author: anoppe

readme-vars.yml

@@ -79,7 +79,8 @@ app_setup_block: |
     roles: [
       { db: "${MONGO_DBNAME}", role: "dbOwner" },
       { db: "${MONGO_DBNAME}_stat", role: "dbOwner" },
-      { db: "${MONGO_DBNAME}_audit", role: "dbOwner" }
+      { db: "${MONGO_DBNAME}_audit", role: "dbOwner" },
+      { db: "${MONGO_DBNAME}_restore", role: "dbOwner" }
     ]
   })
   EOF