Store method arguments in each traceback frame.

This augments the frame data, stored in the Track.details, with the method arguments of each frame in the traceback.

The relevant test is here: https://github.com/rentlytics/django-tracking/blob/86262a7a9e941ef13d5251971f9c9c820cf9fdb0/tracking/tests/test_shortcuts.py#L77-L78