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/clientmanager_test.go

@@ -0,0 +1,20 @@
+package mon
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"go.mongodb.org/mongo-driver/mongo/integration/mtest"
+)
+
+func TestClientManger_getClient(t *testing.T) {
+	mt := mtest.New(t, mtest.NewOptions().ClientType(mtest.Mock))
+	defer mt.Close()
+
+	mt.Run("test", func(mt *mtest.T) {
+		Inject(mtest.ClusterURI(), mt.Client)
+		cli, err := getClient(mtest.ClusterURI())
+		assert.Nil(t, err)
+		assert.Equal(t, mt.Client, cli)
+	})
+}