Integrate the new Location class

- the old `UTMCoordinate` class becomes the new `Location` class
- its main purpose is to represent locations in both lat-long
  coordinates as well as in the UTM system
- remove `Address.__init__()` and `City.__init__()` methods as they
  are not executed for entries retrieved from the database
- simplfiy the `Location.__init__()` => remove `relative_to` argument

setup.cfg

@@ -135,6 +135,9 @@ per-file-ignores =
     src/urban_meal_delivery/db/__init__.py:
         # Top-level of a sub-packages is intended to import a lot.
         F401,WPS201,
+    src/urban_meal_delivery/db/utils/__init__.py:
+        # Top-level of a sub-packages is intended to import a lot.
+        F401,
     tests/*.py:
         # Type annotations are not strictly enforced.
         ANN0, ANN2,