User CLI: Configurable Log Level

[maddisondavid]

Is your feature request related to a problem? Please describe.
The Log Level in the User CLI is currently hard coded to ERROR. This makes it hard to debugging connection issues, such as SSL certificate issues.

Describe the solution you'd like
Make the Log Level configurable via configuration argument

Describe alternatives you've considered
None.

Additional context

• https://github.com/pravega/pravega/blob/master/cli/user/src/main/java/io/pravega/cli/user/UserCLIRunner.java#L50