New CamPUG code of conduct

[Tibs]

I have added a code of conduct for the group, at https://github.com/campug/organisational/blob/master/CodeOfConduct.rst

It is referenced off our meetup.com "About us..." page.

I borrowed heavily from the US PyCon template, as it seems that PyConUK will be doing as well. Hopefully we never need this statement, but I don't believe it restricts anything we were going to be doing anyway.

All the best,

Tibs