Display 'alternatives' page before redirecting to OpenCollective

[keunes]

Short description: A page to which we can link to from the contribute page (instead of directly linking to OpenCollective), with three options/suggestions: donate to your favourite creator (deeplink to Stats page if viewing from Android), donate time to AntennaPod (link to contribute page), donate money (link to OpenCollective).

Location: antennapod.org/donate

Why have this: We hardly need money, and already have quite a bit. Podcasters probably need it more than we do. Providing a link to the stats screen is probably the best to make it concrete.

More info: For text inspiration, see this tweet. For code inspiration, probably look at subscribe deeplink.