MacOS app uninstaller

[rltakashige]

When deleting the app, the plists persist. The main issue here is network setup.

A simple uninstaller or even a cleanup script would prevent us leaving the host computers in weird states. Even though it's likely that we will soon no longer require this network setup script, this may still be important to those who have already installed the app.

[AlexCheema]

@samiamjidkhan can you take a look please.

We will remove the network setup script soon (I think). So main thing is looking into removing the plist cleanly and robustly.