Description:

Introduce a feature gate to switch between two upgrade constraint semantics. When:

• Disabled - operator-controller uses legacy semantics
• Enabled (default) - operator-controller uses semver

Background:

We need to implement a feature gate as per the RFC.

Acceptance Criteria:
The feature gate can be enabled or disabled by passing the following flag to the manager binary:

--feature-gates=ForceSemverUpgradeConstraints=true 

This functionality will be built on top of operator-controller’s existing feature gate mechanisms which is based on the k8s.io/component-base/featuregate package.