Create funding-manifest-urls

[koppor]

To be able to participate in https://floss.fund, we need a well-known file. (Source: https://floss.fund/funding-manifest/)

https://www.jabref.org/.well-known/funding-manifest-urls

content:

https://github.com/JabRef/jabref/blob/main/funding.json

Side note: Current funding for GitHub is configured at https://github.com/JabRef/jabref/blob/main/.github/FUNDING.yml.

[tobiasdiez]

Just create the file here: https://github.com/JabRef/JabRefOnline/tree/main/public/.well-known

[koppor]

@tobiasdiez Tobias wanted it to have the other way round... OK for me.