feat: use mongodb official driver instead of mgo (#1782)

* wip: backup

* wip: backup

* wip: backup

* backup

* backup

* backup

* add more tests

* fix wrong dependency

* fix lint errors

* remove test due to data race

* add tests

* fix test error

* add mon.Model

* add mon.Model unmarshal

* add monc

* add more tests for monc

* add more tests for monc

* add docs for mon and monc packages

* fix doc errors

* chhore: add comment

* chore: fix test bug

* chore: refine tests

* chore: remove primitive.NewObjectID in test code

* chore: rename test files for typo

core/stores/mon/util.go

@@ -0,0 +1,25 @@
+package mon
+
+import (
+	"strings"
+	"time"
+
+	"github.com/zeromicro/go-zero/core/logx"
+	"github.com/zeromicro/go-zero/core/timex"
+)
+
+const mongoAddrSep = ","
+
+// FormatAddr formats mongo hosts to a string.
+func FormatAddr(hosts []string) string {
+	return strings.Join(hosts, mongoAddrSep)
+}
+
+func logDuration(name, method string, startTime time.Duration, err error) {
+	duration := timex.Since(startTime)
+	if err != nil {
+		logx.WithDuration(duration).Infof("mongo(%s) - %s - fail(%s)", name, method, err.Error())
+	} else {
+		logx.WithDuration(duration).Infof("mongo(%s) - %s - ok", name, method)
+	}
+}