Utility to check configuration cannot be run prior to init

[dlmarion]

Describe the bug
The CheckServerConfig class that checks the Accumulo configuration, run via the check-server-config command, cannot be run before an instance is initialized.

Versions (OS, Maven, Java, and others, as appropriate):

• Affected version(s) of this project: 4.0.0-SNAPSHOT, but may go back to 2.1.0

To Reproduce
Steps to reproduce the behavior (or a link to an example repository that reproduces the problem):
Run accumulo check-server-config without an instance initialized

Expected behavior
Expected to validate the configuration regardless of cluster state

[kevinrr888]

I'll take a look at this, if you aren't already.
A ticket I'm currently working on (#4892) would involve moving this check, so would be nice to fix this before I make those changes.

[dlmarion]

@kevinrr888 - I'm not currently looking at this.

[kevinrr888]

Completed from #5073