fixes #1691 - allow searching for fact values for hosts inside a hostgroup

Fixes puppetclasses search with pg database

The request is sorting the results on a field that isn't in the DISTINCT
SELECT'ed columns and pg doesn't like it.
Fixes #1607

we don't change mac/ip by default

This seems to be a bit tricky as facter not always report the correct mac.

managed hosts will not be auto updating by default, however one could still
define the ignore_puppet_facts_for_provisioning settings.

fixes #1115 Host parameters are not available via the API

don't allow to delete a provisioning template when its assigned to an OS default template

ensure that facter mac addressed and formatted correctly when imported into foreman

ensure that you can't delete a compute resource while its used - fixes #1683

ptable, arch and medium errors where not always visible in the UI when saving a host

code comments typos

ensure that autosign entries are removed when using ssh based provisioning.

this is required, as we changed the ssh part to be post db commit.