Add "donate" link to site

[yochannah]

This should probably be a page with as many "easy" ways to support us as possible.

• Stripe link: https://donate.stripe.com/fZe9D71dT9Y36aY6oo
• GitHub sponsors
• Other?

[pherterich]

• Back when we did some research, the PayPal donate button seemed straightforward.
• I just seen someone use this https://liberapay.com/ which seems more value aligned at first sight

[NPDebs]

@pherterich - do you have capacity to set up an account with Liberapay, using OLS finance credentials? 🙏

@Tajuddeen1 and I will then proceed to add info about this (and other donation methods) in a dedicated part of the website where it's very visible?