Adding MIT license

[SteveMcGrath]

As previous contributors I'd like to ask your permission to add the MIT license to this repository.
@eerichmond @wschoot @mattlorimor @lfaoro

[mattlorimor]

+1 lgtm

[wschoot]

Sure!

[SteveMcGrath]

I think @eerichmond is the only one of you not to respond yet. Here are the commits he has submitted:

https://github.com/SteveMcGrath/docker-nessus_scanner/commits?author=eerichmond

Also thanks for the PR @lfaoro, making my life easy ;)

[lfaoro]

anytime Steve ;)

[lfaoro]

Eric hasn't pushed any code since Feb9, maybe he's on vacation -- unless you need unanimity for this, I believe the majority vote should be enough to settle the case :)