I2P donations links & update

@nextloop Regarding the donations info, I see that the Donate link is invalid, can you share a valid one? The other addresses are ok?

Donate: https://geti2p.net/en/get-involved/donate
FlattrID: '13523'
Bitcoin: 1BPdWwovytfGdBwUDVgqbMZ8omcPQzshpX
Litecoin: LM7DTXGHBzh7xeo7ZSWR6hs9s4oVAUsw4E