[documentation] Add info about open source licensing of software

The official line on open source licensing your software is here: https://researchsupport.admin.ox.ac.uk/reporting/openaccess#collapse393821

I’ve spoken with OUI about this recently, and they say that in practical terms if you think your code might have commercial value then you should get approval from your HoD. I’d like to get in place some blanket approval from WIN HoDs which means we don’t have to go to them for approval in every instance, especially if it's lilt chances of code for analysis cf. whole software packages.

The “safest” option (in terms of protecting University IP) would be to use a CC-BY-NC-SA-2.0, so it cannot be used for commercial purposes, with a “share alike” to stop anyone else passing it on for commercial use. You could add a note at the top of the license requesting that anyone interested in commercial use should contact you.

For the Copyright notice, you should include:

“Copyright, 2021, University of Oxford. All rights reserved"

As per the examples here: https://innovation.ox.ac.uk/university-members/commercialising-technology/ip-patents-licenses/software-copyright/.