[Telemetry] Update all WPR json files to the new format.

tools/perf/page_sets/data/maps.json

 {
-    "description": "Describes the Web Page Replay archives for a story set. Don't edit by hand! Use record_wpr for updating.", 
     "archives": {
-        "maps_002.wpr": [
-            "http://localhost:10020/tracker.html"
-        ], 
-        "maps_004.wpr": [
-            "http://localhost:8000/performance.html"
-        ]
-    }
+        "http://localhost:10020/tracker.html": {
+            "DEFAULT": "maps_002.wpr"
+        },
+        "http://localhost:8000/performance.html": {
+            "DEFAULT": "maps_004.wpr"
+        }
+    },
+    "description": "Describes the Web Page Replay archives for a story set. Don't edit by hand! Use record_wpr for updating.",
+    "platform_specific": true
 }