Add ability to show a per-command usage + apply "correct indentation".
Add the "ncp top" command, allowing to search all the violation history.

Original pull request:
https://github.com/NoCheatPlus/NoCheatPlus/pull/24

This probably is not the final implementation, but it allows some
minimal freedom:
* Specify number of entries to show.
* Specify check types (and groups!).
* Specify what to sort by.

There might be need for some merged view, combining several different
check types somehow, or just shortcuts for specific selections, e.g. for
fighting-related checks.

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+ Fix root command not showing sub commmand usage.