Enable debug cookiecutter logging for deep debug

[rmartin16]

Changes

• Configure logging for cookiecutter before generating a template via cookiecutter.log.configure_logger()
• This enables cookiecutter's debug output when Briefcase's "deep debug" is enabled via -vv
• The changenote is misc since we already have a feature note for the addition of -vv support

Notes

• cookiecutter uses the notorious logging package for its logging
  • By default, it appears that cookiecutter only configures logging handlers for its logging when using its CLI; therefore, cookiecutter doesn't enable any handlers for its logger when Briefcase generates a template.
  • Although, perhaps notably, they also don't configure a NullHandler by default....so, cookiecutter is likely to be subjected to a default handler if one is configured....but such is the life of using logging...
  • At any rate, since no handlers were configured before, this changes cookiecutter logging to output INFO and above by default.
  • Although, cookiecutter only appears to use logger.debug() and logger.error() right now...so, it shouldn't matter in reality.
  • Finally, cookiecutter deletes any existing handlers when configure_logger() is called....so, it is safe to call multiple times without concerns about duplicating handlers for the logger.
• Additionally, I couldn't call configure_logger() in BaseCommand.__init__() because verbosity won't be set until parse_options() is called...and verbosity can technically change (although, it doesn't currently).

PR Checklist:

• All new features have been tested
• All new features have been documented
• I have read the CONTRIBUTING.md file
• I will abide by the code of conduct

[freakboy3742]

Looks great. I can't imagine we'll need to turn this on very often, but it's good to know we have the option.