Feature #3914 Set taxonomies from user defaults on login

This PR allows users to have default taxonomies. These can be set on the users/edit form, although something like what @mccun934‎ suggested (http://projects.theforeman.org/attachments/download/654/org-selector-fav.png) would be nice to have in the future. I preferred to wait until inheritable taxonomies (https://github.com/theforeman/foreman/pull/1105) gets merged so that this can go in 1.4.