[schema][database] Improve path pattern

Now allows to use nfs

beat/core/schema/database/1.json

@@ -9,7 +9,7 @@
 
     "root_folder": {
       "type": "string",
-      "pattern": "^(/[^/]+)+$"
+      "pattern": "^((file://)?(/[^/]+)+|nfs://[a-z0-9.-_]+:(/[^/]+)+)$"
     },
 
     "protocols": {