Add logging

[RobinL]

Should help us solve #41, and I think is generally useful for any future debugging.

Use in Jupyter Lab like:

import logging 
logging.basicConfig()  
logging.getLogger("pydbtools").setLevel(logging.DEBUG)

You get out a log like (i've replaced some of the strings with REDACTED)

DEBUG:pydbtools.wrangler:Modifying function create_temp_table
DEBUG:pydbtools.wrangler:
{'boto3_session': Session(region_name='eu-west-1'),
 'sql': 'REDACTED',
 'table_name': 'pc_with_REDACTED'}

[RobinL]

I think I misunderstood how pprint works - just a sec while I fix