[VOL-2471] Update library to use package logger

This commit consists of the following:
1) Add a GetLogLevel() API to make it easier to use specific
logger.   There is also the V() API that kind of do something
similar.
2) Add a common.go file to some heavily used packages in order
to dynamically set their log level and also to a set a specific
logger per package.
3) Use a per package logger for some of the heavily used packages
for improved performance.

Change-Id: If22a2c82d87d808f305677a2e793f8064f33291e
diff --git a/pkg/db/backend_test.go b/pkg/db/backend_test.go
index 6d2fb8a..fdd9071 100644
--- a/pkg/db/backend_test.go
+++ b/pkg/db/backend_test.go
@@ -18,7 +18,6 @@
 
 import (
 	"context"
-	"github.com/opencord/voltha-lib-go/v2/pkg/log"
 	"github.com/opencord/voltha-lib-go/v2/pkg/mocks"
 	"github.com/phayes/freeport"
 	"github.com/stretchr/testify/assert"
@@ -29,10 +28,6 @@
 	"time"
 )
 
-func init() {
-	log.AddPackage(log.JSON, log.FatalLevel, nil)
-}
-
 const (
 	embedEtcdServerHost = "localhost"
 	defaultTimeout      = 1
@@ -48,15 +43,15 @@
 	var err error
 	embedEtcdServerPort, err = freeport.GetFreePort()
 	if err != nil {
-		log.Fatal(err)
+		logger.Fatal(err)
 	}
 	dummyEtcdServerPort, err = freeport.GetFreePort()
 	if err != nil {
-		log.Fatal(err)
+		logger.Fatal(err)
 	}
 	peerPort, err := freeport.GetFreePort()
 	if err != nil {
-		log.Fatal(err)
+		logger.Fatal(err)
 	}
 	etcdServer := mocks.StartEtcdServer(mocks.MKConfig("voltha.db.test", embedEtcdServerPort, peerPort, "voltha.lib.db", "error"))
 	res := m.Run()