Fixes #17483 - async task creation returns 202

Includes task link in response

Fixes #15779 - make background processing available

Fixes #16739 - unify parameters permissions

Fixes #17403 - enable exporting of templates

Fixes #17200 - Add option datacenter to compute resource

Fixes #16646 - Add ability to plugins to modify index scope

Fixes #16962 - Typo on domains welcome page

Fixes #6492 - ipmi_boot permission renamed to ipmi_boot_hosts

Authorizer expects permission names to follow a convention
'action'_'controller'. However this permission was not following it, and
this prevented the permission from being applied properly.

Before this fix, only admins could call ipmi_boot. I've also added a...

Fixes #16813 - improve error messages for associations

fixes #16725 - add plugin extension point for smart proxies