Fix Deployment selector collision with kuadrant-operator

[mikenairn]

Summary

The limitador-operator Deployment uses a generic control-plane: controller-manager selector that collides with the kuadrant-operator when both run in the same namespace. Use a unique selector.

Acceptance Criteria

• Deployment selector uses a unique label (e.g. app: limitador-operator or similar)
• No collision with kuadrant-operator or other child operators in the same namespace

References

• RFC 0019: Kuadrant Operator Consolidation
• Parent issue: Kuadrant Operator Consolidation architecture#164