Dead Code Removal https://github.com/gardener/machine-controller-man…

[elankath]

Dead Code Removal #622

This commit removes dead and deprecated code from the machine controller manager.

What this PR does / why we need it:
This commit removes dead and deprecated code from the machine controller manager. The machine controller is now launched by individual providers and not by the main MCM. Old Migration code from old provider specific machine classes to harmonized machine class has also been removed..

• All provider specific types removed from pkg/apis/machine/types.go and api clients regenerated using make generate
• All migration code from provider specific classes to common MachineClass removed.
• Driver migration method removed
• Deprecated MCM flags removed.
• Removal of provider specific machine classes in kubernetes/crds
• Removal of provider specific machine class yamls in kubernetes/machine_classes
• Removal of old node drain code since this is now handled by the machine controller code present in pkg/util/provider/drain/drain.go which is invoked by platform specific providers.
• Some minor refactoring of routines and constants to adapt to the above.

Which issue(s) this PR fixes:
#622

Special notes for your reviewer:
This change breaks compilation in individual provider repos which need to be updated. Removal of Driver.GenerateMachineClassForMigration needs to be conveyed to other stakeholders.

Release note:

Removal of the following flags (and corresponding fields in associated structs): 'machine-creation-timeout' 'machine-drain-timeout', 'machine-pv-detach-timeout', 'machine-health-timeout=10m', 'machine-safety-apiserver-statuscheck-timeout', 'machine-safety-apiserver-statuscheck-period', 'machine-safety-orphan-vms-period', 'machine-max-evict-retries', 'node-conditions', 'bootstrap-token-auth-extra-groups', 'delete-migrated-machine-class'. The MCM no longer accepts these flags since these are options handled by the Machine Controller invoked by platform specific provider launchers.

Deletion of 'Driver.GenerateMachineClassForMigration'. Providers need to adapt to this.

[CLAassistant]

All committers have signed the CLA.

[himanshu-kun]

In addition to the changes requested, kindly also remove the in-tree documentation related to how to deploy MCM

The following changes should also be done:
Other files related to doc need to be removed :

• Delete Kubenetes/secrets and docs referencing it
• Delete Kubernetes/deployment/in-tree and docs referencing it
• Sample machine object should be updated here https://github.com/elankath/machine-controller-manager/blob/e6a1bd8a076edc94e3f3891dedcdd7dd8e754199/kubernetes/machine_objects/machine.yaml#L12

[himanshu-kun]

also pls remove the deprecated files from this file here https://github.com/elankath/machine-controller-manager/blob/ff4c295bdc2b1a2131b075795309e6f20900108a/kubernetes/deployment/out-of-tree/deployment.yaml#L24

[himanshu-kun]

/lgtm