Move size.py to types

Signed-off-by: Katarzyna Treder <katarzyna.treder@h-partners.com>

test/functional/tests/cache_ops/test_concurrent_flushes.py

@@ -16,7 +16,7 @@ from storage_devices.disk import DiskType, DiskTypeSet, DiskTypeLowerThan
 from test_tools.fio.fio import Fio
 from test_tools.fio.fio_param import IoEngine, ReadWrite
 from test_utils.output import CmdException
-from test_utils.size import Size, Unit
+from types.size import Size, Unit
 
 
 @pytest.mark.parametrize("cache_mode", CacheMode.with_traits(CacheModeTrait.LazyWrites))