Remove config import from init to fix scaffold usage

[pjbull]

• Remove config import from __init__.py (not needed and also breaks since it is there in non-scaffold scenario)
• Refactor some repeated code
• Add import and import config tests
• Add changelog

Closes #370

[jayqi]

not needed

The main thing that happens in config right now that is valuable to auto-execute is this bit:

cookiecutter-data-science/{{ cookiecutter.repo_name }}/{{ cookiecutter.module_name }}/config.py

Lines 24 to 32 in bbfa151

	# If tqdm is installed, configure loguru with tqdm.write
	# https://github.com/Delgan/loguru/issues/135
	try:
	from tqdm import tqdm
	logger.remove(0)
	logger.add(lambda msg: tqdm.write(msg, end=""), colorize=True)
	except ModuleNotFoundError:
	pass

[pjbull]

The main thing that happens in config right now that is valuable to auto-execute is this bit:

Ah, that's a good point. Added back in.

[chrisjkuch]

LGTM!

Just summarizing for my own understanding / posterity:

• We weren't appropriately removing import config from __init__.py when we removed all the boilerplate code, which failed at import time because config.py no longer existed
• When the boilerplate was present, we weren't importing config from the right place leading to an import error
• We now import the config from the right place and remove it when boilerplate is removed, and we test that both of those work as expected in the live tests

[pjbull]

Just summarizing for my own understanding / posterity:

Nailed it! 🔨