scope templates by taxonomy.

Fixes #2000 - display the alternate taxonomy when editing a location or org

filtered users include admins, except in taxonomy form where it is no longer relevant to select admin users.

Allow admin users to join Orgs

Add organization and location to foreman.

This feature allows foreman to provide multi location, multi tenant and
multi organizations capablities.

the idea is that resources within foreman (e.g. hosts, subnets, users,
environments etc) can belong to one or more locations and organization,...