Oracle DR: Complete migration to PowerShell scripts and cleanup

Changes:
- Remove obsolete .cmd scripts (cleanup_database.cmd, rman_restore_from_zero.cmd, rman_restore_final.cmd)
- Update weekly-dr-test-proxmox.sh to call PowerShell scripts with /SILENT parameter
- Add initROA.ora configuration file for reference

All DR test scripts now use PowerShell for SSH compatibility
Resolves input redirection issues with Windows SSH

Co-authored-by: factory-droid[bot] <138933559+factory-droid[bot]@users.noreply.github.com>

oracle/standby-server-scripts/weekly-dr-test-proxmox.sh

@@ -400,7 +400,7 @@ run_dr_test() {
                 log "STEP 6: Running cleanup"
 
                 ssh -p "$DR_VM_PORT" "$DR_VM_USER@$DR_VM_IP" \
-                    "D:\\oracle\\scripts\\cleanup_database.cmd" 2>/dev/null
+                    "powershell -ExecutionPolicy Bypass -File D:\\oracle\\scripts\\cleanup_database.ps1 /SILENT" 2>/dev/null
 
                 cleanup_freed=8
                 track_step "Cleanup" true "Database cleaned, ~${cleanup_freed}GB freed" "$step_start"