Support donations

[kumar303]

This is the gist of what we need to accept donations:

• Submit payment without signing in
• Pay an arbitrary amount

[brampitoyo]

Another question that might be relevant is whether we need to design the “How much would you like to donate?” interface, or if that’s something for the donation page to handle. My guess is the latter.

[andymckay]

Nah, let's leave that to the website starting the donation.