Refactor driver interface to encapsulate the orchestration
strategy. This first patch only refactors the main driver
operations. A follow-on will handle the state synchronization
and removing the poller from the conductor.
1. Make driver interface abstract
2. Move external cluster operations into driver interface
3. Make Heat-based driver abstract and update based on
driver interface changes
4. Move Heat driver code into its own module
5. Update existing Heat drivers based on interface changes
The 2 k8s atomic drivers we currently support are added to the
same driver. This breaks ironic support with the stevedore
work I'm currently doing.
With stevedore, we can choose only one driver based on the
server_type, os and coe. We won't be able to pick a driver and
then choose an implementation bases on server_type.
Partially-Implements: blueprint magnum-baremetal-full-support
Co-Authored-By: Spyros Trigazis <firstname.lastname@example.org>