text: Title: [Suggestion] Remove print statements in `handler.py`
  Body: ## Context
  
  I have gone thru some effort to reduce my CloudWatch logs. By default Zappa was logging a lot of things that I didn't use to CloudWatch which was costing me $100s / mo. 
  
  The best solution I found to suppressing logs was this code in `app.py`:
  
  ```
  logging.getLogger('boto3').setLevel(logging.ERROR)
  logging.getLogger('botocore').setLevel(logging.ERROR)
  logging.getLogger('s3transfer').setLevel(logging.ERROR)
  logging.getLogger('urllib3').setLevel(logging.ERROR)
  logging.getLogger('requests').setLevel(logging.ERROR)
  logging.getLogger('zappa').setLevel(logging.INFO)
  logging.getLogger('chardet.charsetprober').setLevel(logging.INFO)
  ```
  
  Now the majority of my logs are due to `print()` statements in `handler.py` which cannot be suppressed in my application code. 
  
  ## Possible Fix
  
  I would like to reduce logging from `handler.py`.
  
  Here are three options:
  
  1. Remove `print()` statements as on the line https://github.com/Miserlou/Zappa/blob/master/zappa/handler.py#L383 
  2. Change the `print()` statements to user a `logger`
  3. Put the `print()` statements behind a `enable_logging` flag