Snowflake OAuth / externalbrowser support

[japborst]

Unfortunately, I don't have a password for my user and can't use Snowflake as a datasource.

My company login is done through OAuth or by setting authenticator=externalbrowser.

See also https://docs.snowflake.com/en/user-guide/admin-security-fed-auth-use.html

[eatonphil]

Good idea!