clean up / format / poetry (#1000)

* stub in poetry for pipenv

* re-add tester image

* add pre-commit / formatting

* fix ghactions

* revert test data whitespace, exclude tests/data

* revert ws

* decruft, rm tox/pipenv

* install dev packages for base image

* add lgtm config to force to py3

tests/test_data_views.py

@@ -1,11 +1,12 @@
 import pytest
-from django.test import Client
 from django.core.management import call_command
+from django.test import Client
+
 from peeringdb_server.models import (
-    User,
     Organization,
     Sponsorship,
     SponsorshipOrganization,
+    User,
 )