fixes #4268 - don't search for host with nil IP on hostname spoofing
fixes #3939 - add option to 'inherit from parent' for hostgroup attributes
fixes #4333 - added multi-select-rails gem
fixes #3307 - add troubleshooting to console page
fixes #3567 Editing an oVirt compute resource can throw errors loading quotas while loading page
fixes #4125 [Openstack] - host with auto assigned IPs can't be deleted
fixes #3912 - add inheritance for locations / organizations
Bug #3214 No taxonomy if host added from puppet rn

When a host is created through a puppet run, no taxonomies are assigned to it.
This PR solves the issue of taxonomy-less hosts in 2 different ways.
1. Default taxonomy
  From now on Setting[:default_taxonomy] will be the taxonomy of choice
  for hosts that are created through a puppet run.
2. Taxonomy from facts
  Two facts, defined by Setting[:taxonomy_fact], will be available to
  users so that they can define these facts in their own hosts. If
  there's a taxonomy in Foreman with the same name as the fact value
  the host will be placed in that taxonomy.

Adapt PR to nested taxonomies