See:
https://github.com/bitcoin/bips/blob/master/bip-0078.mediawiki
Adds a new module jmclient.payjoin which implements
the full sender workflow from a BIP21 uri to a
payjoin broadcast, state is managed in JMPayjoinManager,
includes all checks as per documentation of
btcpayserver (and later, BIP78).
Added simple client and server implementations in
test/payjoinclient.py and test/payjoinserver.py
which allow a full end to end test on regtest.
Add TLS support to payjoin tests:
Note: the jmclient.payjoin module already
supports TLS by default (Agent object), but
here we add the ability to test without
certificate verification. Both test/payjoinclient.py
and test/payjoinserver.py now support TLS, but
the server needs a key and certificate in its
directory to run.
Adds BIP78 payjoin option to sendpayment.py
Users can use a bip21 uri with the "pj" field to
send a payment to a remote server.
Removes require_path_templates setting from KeyStore call
in PSBTWalletMixin.sign_psbt
Adam Gibson