* performance (less queries executed)
* disable tracking in tests (faster)
* use with_user instead of sudo
* the double for loop in _compute_route_ids actually generates one more
query as the simple one in this commit (thanks to the cache)
* extract a method
* the parent locations can be found using 'parent_of' which will use the
parent_path under the hood (example: 1/7/8 will return locations 1, 7,
8)
