add payjoin support #686

Job	Run time
Rust fmt	11s
Build WASM	58s
Build and test (1.65.0, default)	1m 16s
Build and test (1.65.0, electrum,sqlite-db)	1m 16s
Build and test (1.65.0, electrum,key-value-db)	1m 15s
Build and test (1.65.0, electrum)	1m 11s
Build and test (1.65.0, esplora-ureq,sqlite-db)	1m 14s
Build and test (1.65.0, esplora-reqwest,sqlite-db)	1m 15s
Build and test (1.65.0, compiler,sqlite-db)	1m 15s
Build and test (1.65.0, rpc,sqlite-db)	1s
Build and test (1.65.0, reserves,electrum,sqlite-db)	1s
Build and test (1.65.0, electrum,verify,sqlite-db)	1m 16s
Build and test (1.65.0, regtest-bitcoin,sqlite-db)	1s
Build and test (1.65.0, regtest-electrum,sqlite-db)	1s
Build and test (1.57.0, default)	1m 5s
Build and test (1.57.0, electrum,sqlite-db)	1m 3s
Build and test (1.57.0, electrum,key-value-db)	1m 4s
Build and test (1.57.0, electrum)	1m 4s
Build and test (1.57.0, esplora-ureq,sqlite-db)	59s
Build and test (1.57.0, esplora-reqwest,sqlite-db)	1m 2s
Build and test (1.57.0, compiler,sqlite-db)	58s
Build and test (1.57.0, rpc,sqlite-db)	1m 1s
Build and test (1.57.0, reserves,electrum,sqlite-db)	58s
Build and test (1.57.0, electrum,verify,sqlite-db)	1m 2s
Build and test (1.57.0, regtest-bitcoin,sqlite-db)	59s
Build and test (1.57.0, regtest-electrum,sqlite-db)	1m 2s
	23m 28s

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