consider setting up a proper onion service to donate-neo

as part of the launch of donate-neo (#80), we tried to migrate the onion service from the static site to donate-neo, but found out it was hosted in onionbalance and that its configuration file format is not compatible with tor-little-t, so we can't "just" migrate over.

considering the onion service never really worked anyways (e.g. donate-static#120 (closed)), this is not a requirement for the launch, but we should really look into making this work, as having donations work under Tor was one of the motivations behind this project in the first place.

i tried to convert the private keys with instructions from GPT-4o (!), which seems to believe the private key is stored in DER format on tor-little-t configurations... but that failed in my experiments.

perhaps @rhatto would know of a trick on this?

otherwise I was down to writing Python code to load the keys and write them back... but since the current thing is just a redirect, perhaps we could "just" make a new .onion service instead.