Rewrite "Managing Workloads" concept page to be truly conceptual

**This is a Feature Request**

Rewrite the "Managing Workloads" page at https://kubernetes.io/docs/concepts/cluster-administration/manage-deployment/ to contain actual conceptual content instead of task-based procedures. The current page is misclassified as a concept page when it contains 100% procedural content.

## Current State

The existing page at https://kubernetes.io/docs/concepts/cluster-administration/manage-deployment/ includes:
- kubectl commands and step-by-step procedures
- Code examples for applying manifests
- Detailed how-to instructions for scaling, updating, and organizing resources
- No conceptual explanation of "what" workload management is or "why" it matters

This content belongs in task pages, not a concept page.

## Proposed Change

Rewrite the page to focus on conceptual understanding:
- **What** workload management means in Kubernetes
- **Why** workload management matters
- **When** to use different management approaches
- **Key principles** and patterns (declarative configuration, progressive rollout, etc.)
- **Comparison** of different strategies (rolling updates vs recreate vs canary)

Remove all procedural content and link to the new task/tutorial pages for "how-to" instructions.

This is dependant on #54122 #54120 #54121

## Related Issues

Part of the larger effort to restructure `/docs/concepts/workloads/management/` (#4497)