LDK Node: add Payjoin support

[kaloudis]

We should be able to use Payjoin Dev Kit (PDK) with BDK and on top of LDK

https://payjoin.org/
https://payjoindevkit.org/

[DanGould]

Dropping some state here that might be useful

• Add Payjoin Receiver Support (BIP 77) lightningdevkit/ldk-node#746 is approaching merge
• https://github.com/payjoin/rust-payjoin/tree/master/payjoin-ffi/javascript we've got javascript bindings using uniffi-bindgen-react-native
• https://github.com/xstoicunicornx/node_payjoin/tree/master There's a javascript integration experiment going on here in Node JS