[Device Service] Move PowerMonitor into the Device Service

content/public/app/mojo/content_utility_manifest.json

 {
   "name": "content_utility",
   "display_name": "Content (utility process)",
   "interface_provider_specs": {
     "service_manager:connector": {
       "provides": {
         "browser": [
           "IPC::mojom::ChannelBootstrap",
           "service_manager::mojom::ServiceFactory"
         ],
         "service_manager:service_factory": [
           "service_manager::mojom::ServiceFactory"
         ]
+      },
+      "requires": {
+        "device": [ "device:power_monitor" ]
       }
     }
   }
 }