Changes:

1. Change default Feeds auth behavior

• always_sign_api_key is False by default unless explicitly set by user
• header_authentication is True by default unless explicitly set by user
• Since RTTF endpoints don’t support signed API keys with any auth method, if the user sets always_sign_api_key=True for RTTF, endpoints throw an error that says “Real Time Threat Feeds do not support signed API keys.”
• For non-RTTF endpoints, always_sign_api_key is set True unless explicitly set by user

1. Support X-Api-Key Header Auth for Iris Endpoints