Improve overshooting logic

[prashanth26]

Issue

Machine safety controller only checks for machine objects while overshooting VMs

Solution

Machine safety controller to check infra VMs instead of machine objects while freezing for overshooting.

[elankath]

Grooming Discussion Results:

1. Nobody knows why current overshooting freeze logic checks for machine object count instead of VM (aka instance) count. History on this was lost and not captured in issue.
2. The use-case for user-driven overshooting freeze is understood but why should automatic freeze be necessary is still not clear. Is it just a nice to have safety net or needed from past experience.
3. Currently only the MachineSet controller ignores replica change when overshooting freeze is enabled. The Machine Deployment controller only logs the overshooting freeze condition.
4. Machine Set Overshooting freeze is separate and independent from Machine Controller lifecycle freeze.
5. Some limited background for original motivation of this feature covered in Garbage collector for machine-controller-manager #3