Add remote signing binary #16606

Job	Run time
RPC and mobile compilation check	1m 25s
Sqlc check	2m 40s
cross compilation	40m 3s
check commits	24m 7s
lint code	4m 9s
sample configuration check	1m 10s
check pinned dependencies (google.golang.org/grpc v1.59.0)	3s
run macOS itest	46m 44s
check pinned dependencies (github.com/golang/protobuf v1.5.3)	6s
run unit tests (btcd unit-cover)	16m 51s
run unit tests (unit tags="kvdb_etcd")	18m 28s
check release notes updated	4s
run unit tests (unit tags="kvdb_postgres")	17m 42s
run ubuntu itests (btcd, backend=btcd cover=1)	36m 16s
run unit tests (unit tags="kvdb_sqlite")	16m 9s
run ubuntu itests (bitcoind, backend=bitcoind cover=1)	47m 58s
run unit tests (btcd unit-race)	36m 12s
run windows itest	5m 37s
run ubuntu itests (bitcoind-notxindex, backend="bitcoind notxindex")	46m 31s
run unit tests (unit-module)	2m 3s
run ubuntu itests (bitcoind-rpcpolling, backend="bitcoind rpcpolling" cover=1)	48m 47s
run ubuntu itests (bitcoind-etcd, backend=bitcoind dbbackend=etcd)	1h 3m 28s
run ubuntu itests (bitcoind-postgres, backend=bitcoind dbbackend=postgres)	1h 26m 2s
run ubuntu itests (bitcoind-sqlite, backend=bitcoind dbbackend=sqlite)	49m 26s
run ubuntu itests (bitcoind-postgres-nativesql, backend=bitcoind dbbackend=postgres nativesql=true)	1h 25m 11s
run ubuntu itests (bitcoind-sqlite-nativesql, backend=bitcoind dbbackend=sqlite nativesql=true)	50m 46s
run ubuntu itests (neutrino, backend=neutrino cover=1)	43m 58s
finish	7s
	13h 12m 3s

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