SNOW-818558: Support configuring file paths for private key authentication

[sfc-gh-hachouraria]

What is the current behavior?

Python Connector requires manually reading and decrypting a private key file (and optional passphrase), documented at https://docs.snowflake.com/en/developer-guide/python-connector/python-connector-example#using-key-pair-authentication-key-pair-rotation

Passing file paths and passphrases directly into the config is not currently supported

The .NET driver supports such an option (via PRIVATE_KEY_FILE and PRIVATE_KEY_PWD): https://github.com/snowflakedb/snowflake-connector-net#create-a-connection

The ODBC driver also supports such options (via PRIV_KEY_FILE and PRIV_KEY_FILE_PWD): https://docs.snowflake.com/en/developer-guide/odbc/odbc-parameters#using-key-pair-authentication

What is the desired behavior?

Support convenience options (e.g. private_key_file and private_key_file_passphrase) that perform reading and decrypting private key files automatically, and reduces the work required to use key-pair authentication with the connector.

How would this improve snowflake-connector-python?

These options would simplify configuring private key authentication in higher level applications such as SQLAlchemy, and Django backend for Snowflake (related issues: Snowflake-Labs/django-snowflake#67 and Snowflake-Labs/django-snowflake#72)

References, Other Background

[sfc-gh-spanaite]

@sfc-gh-anugupta Can you please review this feature request?