Reorganized commands

[ArbaazKhan1]

Closes issue #6140

Clarified confusion between different usages of help and added -? as an alias for --help

Added new Zookeeper command group (zk) and consolidated zoo related sub-commands into it:

• dump-zoo
• restore-zookeeper
• zoo-info-viewer
• zoo-prop-editor
• zoo-zap
• zk-cli

Added new Check command group and consolidated troubleshooting/ verification commands into it:

• check
• missing-files
• verify-tablet-assignment

[ctubbsii]

Some of the subcommand names can be further updated to drop "zk" or "zoo" from their names, so instead of "bin/accumulo zk zk-cli", it is just "bin/accumulo zk cli". Also "check" subcommand can be renamed to "system", so it is "check system" instead of "check check".

Also, can you screenshot (or copy/paste into a ``` codeblock) the output of bin/accumulo help after these changes? It helps show the overall user experience improvement for the command renames.

Also, in the description/title/class names, "ZooKeeper" should be spelled with a capital K whenever possible, for consistent branding.