setup 3rd party / apt repo for jdiskmark

[jamesmarkchan]

setup apt or ppa repo for jdiskmark to allow users to install with sudo apt install jdiskmark

this will allow us to configure for debian universe to improve accessibility on debian and ubuntu systems.

@jamesmarkchan You can go ahead and assign me the task of setting up the 3rd party repo. Once that's done, I can look into what it takes to get into Debian Universe. (It's probably easier once we have our own repo.) Getting into Universe would require that all of the code is GPL'ed.

Originally posted by @jslcom in #15