fixes #17407 - add a new hosts dashboard widget

Fixes #1556, #11615 - Remove puppet rdoc support

Puppet rdoc support has been broken for a long time. Removing it from
Foreman.

Fixes #17439 - Moved facet base to a concern

If the plugin that wants to create a new facet doesn't want to
take the inheritance slot (for example if it already has some
base class), it can `include` the new concern.

Fixes #16422 - Foreman API throws ruby exception with ovirt network API

Passing a 'nil' resource_class to the `scope_for` method will always result in a 500 as you cannot call `.where` on nil.

fixes #11127 - show error when rebuild reboot fails

Fixes #17483 - async task creation returns 202

Includes task link in response

Fixes #17296 - Add setting access_unattended_without_build

Fixes #16935 - Allow : & . device ID if there isnt one set

Fixes #15779 - make background processing available

Fixes #17343 - set deep munge config off

deep_munge was introduced as a solution to keep
Rails secure by default which results in
'empty array becomes nil in params'.
Thats why, set deep_munge config off in application.rb.
Also, added changes which will cast param argument to string...