VOL-2154 : Moving back db/model to voltha-go repo

- Package imports and dockerfiles updated
- Left backend.go in voltha-lib-go

Amendments:

- Adjusted proto imports in unit tests
- Adjusted references to db/model in unit tests
- Integrate voltha-lib-go updates

Change-Id: I2d168c516a238222f0371a7bcb672d2b06796838
diff --git a/go.sum b/go.sum
index ce7af5d..3278b61 100644
--- a/go.sum
+++ b/go.sum
@@ -192,8 +192,8 @@
 github.com/onsi/ginkgo v1.6.0/go.mod h1:lLunBs/Ym6LB5Z9jYTR76FiuTmxDTDusOGeTQH+WWjE=
 github.com/onsi/gomega v1.4.2 h1:3mYCb7aPxS/RU7TI1y4rkEn1oKmPRjNJLNEXgw7MH2I=
 github.com/onsi/gomega v1.4.2/go.mod h1:ex+gbHU/CVuBBDIJjb2X0qEXbFg53c61hWP/1CpauHY=
-github.com/opencord/voltha-lib-go/v2 v2.2.9 h1:lnBDQI7HqUucwaNS0A0jWXVpa+CiGVdYKe8k1YKHx9U=
-github.com/opencord/voltha-lib-go/v2 v2.2.9/go.mod h1:Hql0xWiBFqYM6WpE5G+w9//NdaIoR9mVzcvVYDxEnZY=
+github.com/opencord/voltha-lib-go/v2 v2.2.10 h1:BbTkuMnIhz1Uwb6oCQIpQFd0ppH12hqxO5ZZWR+eGog=
+github.com/opencord/voltha-lib-go/v2 v2.2.10/go.mod h1:Hql0xWiBFqYM6WpE5G+w9//NdaIoR9mVzcvVYDxEnZY=
 github.com/opencord/voltha-protos/v2 v2.0.1 h1:vcE0XxNVeu0SED0bW2lf2w24k/QMFrFqMexuedIyTEg=
 github.com/opencord/voltha-protos/v2 v2.0.1/go.mod h1:6kOcfYi1CadWowFxI2SH5wLfHrsRECZLZlD2MFK6WDI=
 github.com/pascaldekloe/goe v0.0.0-20180627143212-57f6aae5913c/go.mod h1:lzWF7FIEvWOWxwDKqyGYQf6ZUaNfKdP144TG7ZOy1lc=