Generalize forcelocal parameter use for user/group resources

Currently, the forcelocal parameter forces the management of local accounts/groups when they are also being managed by some other NSS. However, this parameter is wrongly coupled with the libuser feature, which is a platform-specific application.

This parameter can also be used on AIX and Windows, but due to the way it was implemented it is impossible to do so.

PUP-9465 and PUP-10168 are tasked with separating the libuser functionality from the useradd/groupadd providers into a separate libuser provider.

When that work is complete, we can work on generalizing the forcelocal parameter:

• add a new feature called manages_local_users/groups
• remove the libuser feature
• make forcelocal require the new manages_local_users/groups feature instead
• update impacted providers accordingly