Add menu regions to integration tests

Adding menu regions.

* DropDownMenuRegion - base drop down menu region class
* UserDropDownMenuRegion - menu located in the top right corner

Partially implements blueprint: selenium-integration-testing

Change-Id: I611b46153d0f38a588ee931c954f771306802f14
Change "Modify Users" to "Manage Members"

Change "Modify Users" to "Manage Members" in the Project, Group and
Domain Panels in-row Actions. This allows us to be consistent with the
tab headings in both panels.

Change-Id: I7f99624efe623d3cb7fe5861c9cd8ceab8ca3661
Closes-bug: #1398224
Merge "Add menu regions to integration tests"