Add page for podcasters on 'funding' links

[keunes]

Short description: A page for podcasters where we explain how they can have their funding links show up in AntennaPod (and where it will show up).

Location: Documentation » For podcasters

Why have this: The AntennaPod project stands for an open podcasting system. To ensure its future, podcasters need funding beyond advertising and buy-outs by platforms. With this page we can encourage users to reach out to podcasters, and hopefully increase the uptake of the funding tag and more income for creators.

More info: https://twitter.com/antennapod/status/1476465703481925634