fixes #14000 - respect custom controller permissions

Allows controller_permission method to override the permission suffix
used in resource_scope, originally from a63aa7c and removed in bb39df2.

Fixes #7494 - added search parameter to index action of usergroups

Fixes #13068 - Adds options to documentation_button and remove css float

fixes #14006 - use URL helpers in mailers

Rails 4.2 deprecates mailers from using _path helpers and from path
helpers being called with only_path => false. They should all be
changed to use _url helpers.

fixes #13978 - replace AR value_to_boolean with our caster

In Rails 4.2, value_to_boolean was moved further into ActiveRecord's
column type classes. Replace the use of this internal method with
Foreman's own well-tested caster.

fixes #13817 - test certificate.subject_alternative_names for presence

Otherwise certificate SAN test is always true even with no SAN. This
results in request_hosts being empty and thus ENC authentication fails.

With test by Dominic Cleal <dominic@cleal.org>

Fixes #6858 - escape HTML tags when update a parameter value in settings

Fixes #13913 - split importing of host and facts

Fixes #13711 - fix subnet/domain validation during creation

fixes #14028 - use image-url for data table asset URLs