We're doing more than designing interfaces here with things like the
survey platform.

Document how active contributors can be sponsored to attend events on behalf of Tails (refs: #14727)

Following up on the "meta" title page change.

Another options would be "Restricted funds deliverables" but that will
sounds like jargon to our workers.

- ikiwiki can't deal with '?' in internal links so we have to use href.
- Using a relative URL in href breaks the offline version.
- So let's use a full blow URL everywhere: https://tails.boum.org/donate/

This should allow us to track it as a custom Piwik campaign parameter.

See:

- https://piwik.org/docs/tracking-campaigns/
- https://piwik.org/faq/how-to/faq_120/

Closes: #11783

/support/learn is meant for people who want to learn Tails but is not
helpful for people who want to teach Tails and moves them out the
Contribute section.

refs: #9845

It's not really documentation but more general information about the
project.

It used to be a list of our different public mailing lists. But now that
we have doc/about/contact we can do better.

It's quite complex and long already, so deduplicating sounds good.