Remove builtins imports

This module is not intended to be used directly in most cases, per:
https://docs.python.org/3/library/builtins.html

None of our usages warrant the explicit import. We also avoid some
confusion as folks dig to see what we are doing to require
importing builtins directly.

evennia/utils/dbserialize.py

@@ -18,8 +18,6 @@ in-situ, e.g `obj.db.mynestedlist[3][5] = 3` would never be saved and
 be out of sync with the database.
 
 """
-from builtins import object, int
-
 from functools import update_wrapper
 from collections import defaultdict, MutableSequence, MutableSet, MutableMapping
 from collections import OrderedDict, deque