Don't log verbose by default

[vidister]

Current behavior:
rcli always logs to stdout. This makes parsing the structured output a pain.

rcli exec -o json device.example.com "show interface" | jq .
parse error: Invalid numeric literal at line 1, column 15

Expected behavior:

Option 1:

• Don't log info/verbose by default
• When -v or --verbose is set, log to stderr
• always log errors to stderr

This is equivalent to the behavior of curl.

Option 2:

• Only log to stdout when no pipe is attached to stdout
  • can be checked using os.ModeCharDevice
• errors log to stderr

I prefer Option 1.

[vidister]

Nevermind, apparently there was an old version of the flake pinned in our repo. The current main logs to stderr.
This reduces the scope of the issue to:

• Only log anything else then error when -v/--version is set.