Build in a step to scan mods with Bandit to improve security

[monkeyman192]

Since the mods which can be written can contain malicious code, it would be good to be able to use bandit to scan the python code which makes up a mod to try and discern any potential threats contained, and not load the mod if there are any found.

[monkeyman192]

This looks like it might actually be trickier than I thought... For one thing, bandit doesn't have any easy way to call it programatically. It is possible, but I found that it doesn't actually detect issues of the type I was expecting (was thinking of detecting malicious code etc).
There is https://github.com/DataDog/guarddog which seems promising, but I think for now this is probably reasonably low priority and so can be moved out of the 0.2 milestone...