Updates pbr requirements

Removes the version from setup.cfg and moves
Windows platdorm requirements to requirements-windows.txt

Closes-Bug: #1404746

Change-Id: Ieadc67e6c320e9712c57d6adf3f3e6df6ae78b75
Adds ADSI based Windows user management

Replaces the Windows user creation and password management
implementation from "NET USER" execution to ADSI COM usage.

Change-Id: I4f95b094c95abb11762943afdb4be26541493159
Closes-Bug: #1404533