lncli: read password from stdin till EOF in unlock #19

Job	Run time
check pinned dependencies (google.golang.org/grpc v1.59.0)	4s
lint code	4m 13s
check commits	3m 21s
cross compilation	29m 41s
check pinned dependencies (github.com/golang/protobuf v1.5.3)	4s
run macOS itest	1h 1m 19s
check release notes updated	6s
RPC and mobile compilation check	2m 21s
sample configuration check	57s
Sqlc check	1m 0s
run ubuntu itests (btcd, backend=btcd)	42m 31s
run unit tests (btcd unit-cover)	16m 39s
run ubuntu itests (bitcoind, backend=bitcoind)	53m 18s
run windows itest	51m 9s
run ubuntu itests (bitcoind-notxindex, backend="bitcoind notxindex")	53m 30s
run unit tests (unit tags="kvdb_etcd")	18m 17s
run ubuntu itests (bitcoind-rpcpolling, backend="bitcoind rpcpolling")	53m 47s
run unit tests (unit tags="kvdb_postgres")	18m 1s
run ubuntu itests (bitcoind-etcd, backend=bitcoind dbbackend=etcd)	1h 11m 49s
run unit tests (unit tags="kvdb_sqlite")	16m 56s
run ubuntu itests (bitcoind-postgres, backend=bitcoind dbbackend=postgres)	1h 28m 34s
run unit tests (btcd unit-race)	34m 28s
run ubuntu itests (bitcoind-sqlite, backend=bitcoind dbbackend=sqlite)	55m 52s
run unit tests (unit-module)	1m 28s
run ubuntu itests (bitcoind-postgres-nativesql, backend=bitcoind dbbackend=postgres nativesql=true)	1h 25m 10s
run ubuntu itests (bitcoind-sqlite-nativesql, backend=bitcoind dbbackend=sqlite nativesql=true)	55m 20s
run ubuntu itests (neutrino, backend=neutrino)	51m 14s
	14h 31m 9s

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