(WIP) (PUP-2628) Add members to groups instead of full list for Windows

Previously, if you wanted to use the group resource you needed to specify the
entire list of members as the windows provider ignored the auth_membership
setting and was always the authoritative list. This ensures that the windows
provider respects the auth_membership setting.
This was a good change, but I wonder if it has implications at all. It is a necessary change to check the setting as a boolean instead of relying on what was specified in the manifest and parsing that to a bool.