chanbackup, server, rpcserver: put close unsigned tx, remote signature and commit height to SCB #12130

Job	Run time
RPC and mobile compilation check	3m 57s
check commits	4m 16s
cross compilation	9m 45s
lint code	4m 41s
check pinned dependencies (google.golang.org/grpc v1.56.3)	4s
check pinned dependencies (github.com/golang/protobuf v1.5.3)	3s
sample configuration check	1m 45s
Sqlc check	1m 9s
run unit tests (btcd unit-cover)	14m 49s
run ubuntu itests (btcd, backend=btcd)	43m 39s
run unit tests (unit tags="kvdb_etcd")	15m 55s
run windows itest	49m 58s
run ubuntu itests (bitcoind, backend=bitcoind)	54m 49s
run unit tests (unit tags="kvdb_postgres")	14m 20s
run ubuntu itests (bitcoind-notxindex, backend="bitcoind notxindex")	55m 1s
run unit tests (unit tags="kvdb_sqlite")	13m 37s
run ubuntu itests (bitcoind-rpcpolling, backend="bitcoind rpcpolling")	54m 46s
check release notes updated	4s
run unit tests (btcd unit-race)	31m 33s
run unit tests (unit-module)	1m 31s
run ubuntu itests (bitcoind-etcd, backend=bitcoind dbbackend=etcd)	1h 10m 7s
run ubuntu itests (bitcoind-postgres, backend=bitcoind dbbackend=postgres)	1h 19m 45s
run ubuntu itests (bitcoind-sqlite, backend=bitcoind dbbackend=sqlite)	55m 46s
run ubuntu itests (neutrino, backend=neutrino)	52m 38s
	10h 33m 58s

Provide feedback