Fixes #20963 - CVE-2017-7535 prevent XSS on org/loc host assign

(cherry picked from commit b8db2f931208992d6bcff44a2d20101637f6c232)

Fixes #20098 - Resolve template_used for image provisioning

At the moment, the method Hostext::OperatingSystem#template_kinds is
unable to handle image-based provisioning. If there is an image, it will
not be able to find it as 'self.compute_attributes' does not exist for...

Fixes #20669 - Append 'clone' to cloned provisioning templates

Fixes #20612 - Fix error rendering when building pxe default

Fixes #20255 - add csv export for hostgroups

Fixes #20553 - br tag now renders to new line

Fixes #19529: Use main_app for redirect in case of plugins

Sometimes when entering the require_mail filter, the plugins context
is carried over and the route cannot be matched. Using main_app ensures
that it will resolve the path from the proper context.

fixes #20453 - build is enabled for cloned host (#4704)

Fixes #20248, #20327 - Respect context in CSV export

Since CSV export is done using an enumerator which is executed by a
different thread to the one that creates it, we need to manually pass in
the context (user, location, organization) to the enumerator.

Fixes #20386 - Allow to identify smart proxy by ip only

This allows setting trusted_puppet_master_hosts to an IP in the
non-https case. This can e.g. be useful when testing ansible fact
importing from another machine.