Accumulo command re-org follow-ons

[dlmarion]

Overall, seems fine. A few things that can be addressed now, or as follow-on:

1. What's the difference between accumulo --help and accumulo help? And, if they are the same, why are the documented in different sections?
2. Also, -? is often an alias for --help. Is that still the case here?
3. Some of the "conf" commands don't seem to be configuration-related (zoo dump is more of a backup than a configuration admin tool); I'm not sure "conf" is right for a section
4. The ZooKeeper commands are a bit spread out, though some are probably related; those probably need consolidated
5. I think instance or even cluster would be better than inst.
6. init seems buried among a bunch of less important commands... I'd kind of expect it to exist alongside other one-off commands that are part of a normal lifecycle like upgrade, and maybe version, but not alongside obscure commands like missing-files and remove-scan-server-references
7. The proc commands to start servers says "Start", but it should probably say "Run". "Start" implies that it detaches and starts in the background, and that you might subsequently be able to run "Stop" commands in the same terminal. But, that's not the case. "Run" is the better verb here, I think, consistent with other tools like jetty:start vs. jetty:run for the jetty-maven-plugin, or 'Thread.start()' vs. 'Runnable.run()' for a more low-level example.

Some of the tools could be organized into a "troubleshooting", "verify", or "check" section. I think "check" is probably the best name of the three, just because it's short, but I don't know if it makes sense with every troubleshooting command.

Originally posted by @ctubbsii in #6131 (review)