Deprecate the nonPrivileged field in Installation CRD

[lucastigera]

Description

Since the iptables version bump to v1.8.8, the non-privileged mode is no longer supported. This PR deprecates the Installation.spec.nonPrivileged field.

Changes:

• Removed the logic that consumes this field in the node render path.
• Marked the field as deprecated in the Installation CRD.
• Added validation: if a user sets the field to Enabled, the Operator sets Calico to Degraded with a clear error message explaining that the feature is deprecated and no longer supported.

Release Note

- Dropped support to the non-privileged mode and deprecated the `Installation.spec.nonPrivileged` field. The Operator ignores this setting and will mark Calico as Degraded if it is set to Enabled.

For PR author

• Tests for change.
• If changing pkg/apis/, run make gen-files
• If changing versions, run make gen-versions

For PR reviewers

A note for code reviewers - all pull requests must have the following:

• Milestone set according to targeted release.
• Appropriate labels:
  • kind/bug if this is a bugfix.
  • kind/enhancement if this is a a new feature.
  • enterprise if this PR applies to Calico Enterprise only.