This change removes pxe_ipmitool and agent_ipmitool. Some tests
and documentation bits are removed, since we no longer have any
classic drivers to provide examples.
The Inspector.create_if_enabled method is no longer used and was
removed. The [inspector]enabled option will be deprecated in
a follow-up.
IRONIC_ENABLED_DRIVERS is removed from devstack to prevent
devstack-gate from injecting the removed drivers into it.
A temporary migration from queens is updated to disable all
classic drivers. It will be removed when the enabled_drivers
option is completely removed.
Change-Id: Iab247e3b3336f90446ef0687edb340cf8282a925
1a07137118