Add patreons to the about page

[dragonDScript]

Patreons are really helpful to this project. We should include them in the about page (like "special thanks" in some games).

Alternatives

A "sponsors" button that redirects to patreon website or our own website and that shows all the protons. This is a simpler approach but personally I'd prefer the first one.

[flavioislima]

@dragonDScript can you improve the ticket description?

[flavioislima]

better do #2018 instead