Add slog structured logging to various controllers and utility functions

- Integrated `slog` logging into the `MirrorPeerSecretReconciler`, `MirrorPeerReconciler`, and `DRPolicyReconciler` controllers.
- Improved error handling and logging for better observability and debugging.
- Replaced klog with slog for consistency across the codebase.

Changes include:
- Added `Logger` field to controller structs to pass and use `slog.Logger`.
- Enhanced logging messages to provide more context, including function names, object names, namespaces, and error details.
- Ensured logs capture both normal operation (e.g., successful updates) and error conditions.

Signed-off-by: vbadrina <[email protected]>

Author: vbnrh