Add images for project cards

[adamltyson]

They're currently a bit boring. Ideally each project would have a logo and this could be used here.

[JoeZiminski]

@adamltyson I think this is done right, it meant like this?

[adamltyson]

A very vague issue raised by me, but I think I meant the cards on this page:
https://neuroinformatics.dev/projects.html