Wiki editing unlocked

[Zitchas]

I'm going to try an experiment here. I have removed the "restrict wiki edits to people with push access" restriction.

I would prefer that we don't replace any of upstream's wiki pages, but we should definitely have pages of our own that document all the code changes present in Delta.

For a lot of it, it should probably mirror upstream's format & layout, with links to upstream, and specify that the changes are for here in Delta.