Clean-up .gitignore

.gitignore

+db.sqlite3
+.idea
+.mypy_cache
 *.pyc
-dev_data.sqlite
+.pytest_cache
 static/
-steering/local_settings.py
-steering/site_media/buttons/b-*.png
-steering/site_media/buttons/s-*.png
-steering/site_media/buttons/r-*.png
-steering/site_media/show_images/*
-steering/site_media/note_images/*
-steering/site_media/host_images/*
-steering/site_media/__sized__/*
-steering/cache/*
-steering/mysql.cnf
-steering/postgresql.cnf
 steering_data_model.png
-venv/
-python/
-.env