check command - Provide the ability to validate configuration / system state with a command

Now that we have the ability to check and validate configuration and system state at a high level, it would be good to get that check to happen by simply running a command. All of that nice information that is now hidden behind debug levels would flow to the console information by default with this.

Related to #1746

Start by reviewing related issue #1746 and the existing high-level configuration and system-state validation behind debug levels. Determine the command entry point and the information that should flow to the console by default; done means a command performs the check and displays that validation output.

Written by the indexing model from the issue text.