[rfq]: add validation to `AddAssetBuyOrder` and `AddAssetSellOrder` RPCs #3450

Job	Run time
Format check	21s
cross compilation	11m 9s
Docker build check	3m 38s
Compilation check	49s
run itests	7m 51s
run itests postgres	20m 41s
Lint check	5m 34s
migration version check	9s
go mod check	21s
RPC check	1m 9s
run LiT tests	15m 39s
sample configuration check	44s
Sqlc check	32s
test vector check	51s
run unit tests (unit-race)	9m 40s
run unit tests (unit-cover)	5m 55s
run unit tests (unit dbbackend=postgres)	5m 48s
finish	5s
	1h 30m 56s

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