twinklexfd: update to use Wikipedia.page, and lots of other fixes

Here it is, guys. It seems to hold together under normal conditions. But it is huge, and there are so many little things to test. Please lend a hand.
Some of the nice stuff:
- now lets you abandon an AfD if someone beat you to it (for NPP)
- hopefully the bugs about incomplete/half-done AfDs should be fixed
- now notifies the owner of the userspace for MfDs in User: and User talk: spaces