Add custom headers, update LICENSE - Issues# 28 & 26 - plus general housekeeping

[sbarbett]

Housekeeping

• modified file structure to be more aligned with best practices
• deleted old obsolete setup.py file
• fixed license section of README.md (Issue#26)
• updated .gitignore with common Python template
• made RestApiConnection class available in __init__.py
• fixed license_files in pyproject.toml (it excepts a list, not a dictionary)
• fixed version in about.py

New Feature(s)

Issue#28

• added constructors to RestApiClient and RestApiConnection classes to support custom HTTP headers (custom_headers)

  from ultra_rest_client import RestApiClient
  client = RestApiClient('username', 'password', custom_headers={"foo":"bar", "user-agent":"hello"})
  zones = client.get_zones()

  Captured header output:

  {
      "Accept": "application/json",
      "Authorization": "Bearer redacted",
      "Content-Type": "application/json",
      "foo": "bar",
      "user-agent": "hello",
      "User-Agent": "udns-python-rest-client-2.2.3"
  }

• added a public method to RestApiConnection which allows modification of headers after client has been instantiated

  client.rest_api_connection.set_custom_headers({"boo":"far","user-agent":"goodbye"})
  zones = client.get_zones()

  Captured header output:

  {
      "Accept": "application/json",
      "Authorization": "Bearer redacted",
      "Content-Type": "application/json",
      "foo": "bar",
      "boo": "far",
      "user-agent": "goodbye",
      "User-Agent": "udns-python-rest-client-2.2.3"
  }

• attempting to set the following headers will raise a ValueError

  • Content-Type
  • Authorization
  • Accept

• updated README.md with example