Add donation buttons

[blryface]

I've recently created the Vital ko-fi so people can help us pay for a dedicated Vital domain, but we haven't mentioned it anywhere publicly yet.

I can set up the GitHub button tomorrow, but I'm not too confident of touching any of our web stuff without breaking them

It should be clarified in #101 and #136 that donations are (at least at the time of writing) specifically to help us pay for a Vital domain, and not to try and profit off of Vital

[KTrain5169]

alright, you can just add a donate button to the footer of the site

[KTrain5169]

shouldn't break anything

[blryface]

im just gonna make pixel do it because I forgor and really shouldn't do this via my phon

[blryface]

bump