CLI should provide a way to see the location of internal cached files and provide a way for them to be cleaned up

[wasaga]

Is your feature request related to a problem? Please describe.

Pomerium CLI stores some cached data such as JWT tokens and config inside OS-dependent locations.
Sometimes the users may need to know the location of those files, and be able to purge them.

Describe the solution you'd like

Provide a subcommand to print location and clean up the data.

Describe alternatives you've considered

Explain any additional use-cases

If there are any use-cases that would help us understand the use/need/value please share them as they can help us decide on acceptance and prioritization.

Additional context

Add any other context or screenshots about the feature request here.