Support user-generated RFQ on `tchrpc.SendPayment` #3524

Job	Run time
test vector check	53s
Sqlc check	35s
go mod check	22s
Docker build check	3m 41s
migration version check	11s
Compilation check	1m 40s
RPC check	1m 8s
sample configuration check	41s
cross compilation	12m 5s
Format check	25s
run itests	11m 31s
run itests postgres	20m 25s
Lint check	2m 41s
run LiT tests	12m 32s
run unit tests (unit-race)	11m 24s
run unit tests (unit-cover)	4m 29s
run unit tests (unit dbbackend=postgres)	6m 14s
finish	5s
	1h 31m 2s

Provide feedback