[3/3]: Implement `Consumer` on `chainWatcher` and resolvers #462

Job	Run time
cross compilation	32m 9s
check pinned dependencies (google.golang.org/grpc v1.59.0)	6s
check commits	31m 11s
lint code	3m 51s
check pinned dependencies (github.com/golang/protobuf v1.5.3)	4s
run macOS itest	34m 32s
check release notes updated	4s
RPC and mobile compilation check	2m 1s
sample configuration check	56s
Sqlc check	29s
run ubuntu itests (btcd, backend=btcd cover=1)	22m 7s
run windows itest	6m 38s
run ubuntu itests (bitcoind, backend=bitcoind cover=1)	30m 15s
run unit tests (btcd unit-cover)	15m 36s
run ubuntu itests (bitcoind-notxindex, backend="bitcoind notxindex")	29m 16s
run unit tests (unit tags="kvdb_etcd")	18m 29s
run ubuntu itests (bitcoind-rpcpolling, backend="bitcoind rpcpolling" cover=1)	29m 21s
run unit tests (unit tags="kvdb_postgres")	17m 16s
run ubuntu itests (bitcoind-etcd, backend=bitcoind dbbackend=etcd)	41m 21s
run unit tests (unit tags="kvdb_sqlite")	15m 38s
run ubuntu itests (bitcoind-postgres, backend=bitcoind dbbackend=postgres)	52m 2s
run unit tests (btcd unit-race)	35m 20s
run ubuntu itests (bitcoind-sqlite, backend=bitcoind dbbackend=sqlite)	31m 32s
run unit tests (unit-module)	1m 6s
run ubuntu itests (bitcoind-postgres-nativesql, backend=bitcoind dbbackend=postgres nativesql=true)	52m 31s
run ubuntu itests (bitcoind-sqlite-nativesql, backend=bitcoind dbbackend=sqlite nativesql=true)	31m 25s
run ubuntu itests (neutrino, backend=neutrino cover=1)	26m 27s
finish	7s
	9h 21m 50s

Provide feedback