Additional Snowflake Connection Parameters

[iireland-ii]

The current snowflake integration assumes a password authentication, snowflake provides additional connection methodologies such as a private_key for engineers to develop services.
-https://docs.snowflake.com/developer-guide/python-connector/python-connector-connect#using-key-pair-authentication-and-key-pair-rotation
-https://docs.snowflake.com/en/user-guide/key-pair-auth

Solution
Add other more secure connection methods to the snowflake_table_retriever class:
Private_key_file
Private_key_file_pwd

[iireland-ii]

I've created a pull request to add this functionality.

#1190