cli: store cluster state in directory (or single-file container)

• log files
• opstrace DNS service credentials
• what else?

Use a convention to translate the cluster name an provider to the path (of directory or single-file container).

That would make it easier to switch between clusters.

There may be downsides, too.

Notes:

• thought often times: cluster name should be in the log file names
• credential files need to have more expressive names, be hidden, and/or otherwise consolidated (only one of both should be needed)

This is brainstorm level.