Implement factory for app_utilities

[hpohekar]

Ideally, the app_utilities module could act as the factory rather than the calling code.

if FluentVersion(self.scheme_eval.version) < FluentVersion.v252:
            self._app_utilities = AppUtilitiesOld(self.scheme_eval)
        else:
            self._app_utilities = (
                self._fluent_connection._connection_interface._app_utilities
            )