Support user-generated RFQ on `tchrpc.SendPayment` #3538

Job	Run time
Compilation check	1m 44s
Format check	25s
cross compilation	11m 51s
Docker build check	3m 42s
run itests	11m 17s
run itests postgres	20m 9s
Lint check	2m 48s
migration version check	17s
go mod check	22s
RPC check	1m 19s
run LiT tests	14m 12s
sample configuration check	38s
Sqlc check	29s
test vector check	55s
run unit tests (unit-race)	11m 12s
run unit tests (unit-cover)	4m 25s
run unit tests (unit dbbackend=postgres)	6m 1s
finish	4s
	1h 31m 50s

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