Add donation links for individual asset submissions and/or for submitters

[willnationsdev]

Previously searched Issues https://github.com/godotengine/asset-library/issues?utf8=%E2%9C%93&q=is%3Aissue+is%3Aopen+donate

Issue Description People have complained frequently about the lack of a paid asset store, but suggestions for changing that have equivalently lead to backlash from the Godot community in regards to opening up the Asset Library to paid assets.

Even if the efforts were outsourced to, say, Itch, where Itch store contents are loaded directly into the editor and people could pay for assets there, you'd still end up with people becoming stingy with their work, going after people for circumventing barriers to get a copy of an asset, and any number of other similar problems that go hand-in-hand with a traditional marketplace.

INSTEAD of doing all of that, a great compromise would be to simply add donation buttons for various websites in the Asset Library windows. This would allow individual plugin and asset developers to receive funding from people who want to support them, but it would also ensure that it is a free / pay-what-you-want model that doesn't create any legal dependencies on ownership of the data.

Note: Maybe we should also support users creating a donation button for their profile that would automatically be added to every Asset page they create?

[bojidar-bg]

Sounds like a great idea to me.

Maybe we can do something like OGA/OpenGameArt for this? There each user has a Patreon button: While each "asset" has the same Patreon link, as well as a Flattr button:

We might include more platforms, such as Liberapay, but it would be helpful to have a list of them.