Port admin-actions API into v3 part2

This patch contains the changes required to adapt the admin-actions
extension and the corresponding unittest to the v3 framework.

Partially implements bp v3-api-extension-versioning

Change-Id: Ib109f52999de8e986c258d8d9d35d8193e8b0851
Merge "Port admin-actions API into v3 part2"