Migrate core/database_util.go to rawdb package #399

Job	Run time
tests (A-B tests, go run build/ci.go test -coverage $(go list ./... \| grep "github.com/XinFinOrg/...	1m 23s
tests (C-[a-m] tests, go run build/ci.go test -coverage $(go list ./... \| grep "github.com/XinFin...	1m 50s
tests (C-[n-o] tests, go run build/ci.go test -coverage $(go list ./... \| grep "github.com/XinFin...	7m 28s
tests (C-[p-z] tests, go run build/ci.go test -coverage $(go list ./... \| grep "github.com/XinFin...	45s
tests (D-I tests, go run build/ci.go test -coverage $(go list ./... \| grep "github.com/XinFinOrg/...	2m 42s
tests (J-N tests, go run build/ci.go test -coverage $(go list ./... \| grep "github.com/XinFinOrg/...	2m 13s
tests (O-S tests, go run build/ci.go test -coverage $(go list ./... \| grep "github.com/XinFinOrg/...	1m 31s
tests (T-Z tests, go run build/ci.go test -coverage $(go list ./... \| grep "github.com/XinFinOrg/...	55s
devnet_build_push	0s
tag_build	0s
devnet_k8_apply	0s
rpc_k8_apply	0s
devnet_send_notification	0s
	18m 47s

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