feat(config): add file and CLI configuration support

[eXamadeus]

Why

Passing in credentials in the code is messy and could cause security issues. This change adds the ability to pull in credentials from the env OR a credentials file. The file logic is based on the XDG standard.

If you have a configuration file on your system or the proper env variables set, you no longer need to provide credentials when you instantiate an Account. You can set the credentials once, then whenever an Account is made, it will pull from the configuration.

What

Two new methods of storing credentials will be supported. Only one is required. The order of precedence will be the configuration file

• Support passing credentials via env variables
  • Set GODADDY_API_KEY to the api key
  • Set GODADDY_API_SECRET to the secret key
• Support XDG-compliant configuration file
  • Add in CLI support for configuring this file using:
    • python -m godaddypy or
    • Account.configure()