Report back what changes were made to logging and require at least one option set

[mozzieongit]

Changes:

• Require at least one of the options to be present (otherwise the command doesn't do anything)
• Enable providing multiple trace targets in a single comma-separated argument to --trace-targets
• Print what has changed.

I got confused that cascade debug change-logging stated that it changed the logging, but I didn't give it any options, so I wondered what it changed to. Turns out it didn't actually change anything.

This PR changes the behaviour to require at least one of the options to be provided, and log what the changes submitted to the server are.

Arguably, now that at least one of the options is required, the verbosity is not really required anymore.

I opted to only set level to required_unless_present_any ..., as not to confuse users with clap's error message stating that both would be required:

error: the following required arguments were not provided:
  --level <LEVEL>
  --trace-targets <TRACE_TARGETS>

Usage: cascade debug change-logging --level <LEVEL> --trace-targets <TRACE_TARGETS>

For more information, try '--help'.

Instead, it only shows --level as required, as that is the option most commonly used I assume.

error: the following required arguments were not provided:
  --level <LEVEL>

Usage: cascade debug change-logging --level <LEVEL>

For more information, try '--help'.

Additionally, the help text states that "at least on option of 'level' or 'trace-targets' is required".

[ximon18]

Nice improvement.