added manger to keep track of go routines in the services (#2869)

- added manager to wait for all go routines to end before exit
- code refactor
- renamed Manafer to Interface and GoRoutineManager to GroupManager
- replaced some go routine calls with manager Add func
- added unit tests for manager

cmd/fetcher/main.go

@@ -22,15 +22,21 @@ import (
 	"github.com/fission/fission/cmd/fetcher/app"
 	"github.com/fission/fission/pkg/crd"
 	"github.com/fission/fission/pkg/utils/loggerfactory"
+	"github.com/fission/fission/pkg/utils/manager"
 	"github.com/fission/fission/pkg/utils/profile"
 )
 
 // Usage: fetcher <shared volume path>
 func main() {
+
+	mgr := manager.New()
+	defer mgr.Wait()
+
 	logger := loggerfactory.GetLogger()
 	defer logger.Sync()
 
 	ctx := signals.SetupSignalHandler()
-	profile.ProfileIfEnabled(ctx, logger)
-	app.Run(ctx, crd.NewClientGenerator(), logger)
+	profile.ProfileIfEnabled(ctx, logger, mgr)
+
+	app.Run(ctx, crd.NewClientGenerator(), logger, mgr)
 }