Fixes: #7336 - VLAN Translation

[bctiemann]

Fixes: #7336

Adds VLANTranslationPolicy and VLANTranslationRule models and all associated UI visualization classes. Provides the ability to associate a VLAN translation policy and all its associated translation rules with a given interface, e.g.

Interface 1:
  Policy 1:
  - 100 -> 200
  - 101 -> 201
  - 102 -> 202

This VLAN translation mapping is then reflected in the Interface's detail page, both in the Addressing section and in an inline table below "VLANs".