Add support for external browser authentication

[dlouseiro]

Is your feature request related to a problem? Please describe.
All personal (non-service account) users in our Snowflake account do not have a password and authenticate via external browser. In the current implementation of the target, it seems that the only support authentication method is basic authentication (user/password).

While this may be the most common authentication method for service accounts and for executions running in a production-like setup, having the possibility to authenticate via browser is quite useful for local executions.

Describe the solution you'd like
For the target to allow browser based authentication.

[dlouseiro]

PR here