Fixes winrm access denied bug for Windows versions 6.0 and 6.1

On Windows Vista, 2008, 2008 R2 and 7, changing the configuration of
the winrm service will fail with an "Access is denied" error if the
User Account Control remote restrictions are enabled.

The solution to this issue is to temporarily disable the User
Account Control remote restrictions.

https://support.microsoft.com/kb/951016

Co-Authored-By: Robert Tingirica <rtingirica@cloudbasesolutions.com>
Closes-Bug: #1379854

Change-Id: I07b61b94900d39ad0aee544e26ee37bbc94bf7b9
Fixed ctypes/wintypes issue

The c_void_p and HRESULT are not accessible from wintypes in Python3.
This patch fixes the issue and it keeps functionality for Python27

Change-Id: I0a1c5d0770a66529528d1e2f7f1ba08368e53fe7
Add FreeBSD support to cloudbaseinit

In order to support FreeBSD in cloudbaseinit, the patch changes the
following:

  * implements a specific osutils class for FreeBSD.

  * the osutils dispatching is done using `platform.system`.
    This offers a better granularity level than `sys.platform` or
    `os.name`.

  * certain plugins can work unchanged on both Windows and FreeBSD.
    In order to have a consistent place for such common plugins,
    a new location is added, 'plugins/common'.

  * refactor filexecutils.py and userdatautils.py, by having a common
    command execution interface, in the new 'executil.py'.

This patch is work in progress.