Log authentication and login failures at the info level, rather than debug

[micahlee]

The generic 401 error response from authenticators (specifically authn-k8s) can have a variety of root causes, some of them not directly related to the authentication credentials themselves, but rather issues with the authenticator configuration.

Currently the way to gather more information for a authentication failures is to increase the log level for Conjur to debug. However, this also turns on logging of all database queries, and because the rotator process executes a SQL query every second for pending rotations, this makes it very difficult to find the information you're looking for.

The proposal to improve this experience is to log authentication failures at the info log level, rather than debug.

[micahlee]

Blocked by #1464

[orenbm]

Unblocked by #1464 as we found no issue in logging these messages in INFO level