DRILL-8499: new util for creating random strings

[pjfanning]

Description

DRILL-8499
Discussed in Drill mailing lists

[cgivre]

LGTM +1

Thanks @pjfanning!
Just a question, but is the license file addition necessary? The reason I ask is that I think there are a few other similar situations in Drill where we copied and slightly modified libraries that are licensed under an Apache license.

[pjfanning]

@cgivre I'm involved in the Incubator PMC and the PMC members try to get all the podlings to be very explicit in their LICENCEs.

The Apache License basically requires you to copy the 3rd party Apache License and Notice into your License and Notice when you borrow code - even if you make some fairly large mods to it.

You don't need to duplicate the standard text of the license but things like copyrights should be copied.
The source header(s) from the original files should be preserved.