Replace the Imp Module With Importlib in More Places

[StabbarN]

Deprecated imp module is still being used.

I get a deprecation warning from bpython (version 0.20) with django-admin shell_plus (https://github.com/django-extensions/django-extensions)

.venv/lib/python3.7/site-packages/bpython/args.py:10: DeprecationWarning: the imp module is deprecated in favour of importlib; see the module's documentation for alternative uses

See https://github.com/bpython/bpython/blob/0.20-bugfix/bpython/args.py#L10

Similar issue #791 and PR #792