Push scalability (#3080)

* Update status through increment
* adds support for incrementing nested keys
* fix issue when having spaces in keys for ordering
* Refactors PushController to use worker
* Adds tests for custom push queue config
* Makes PushController adapter independant
* Better logging of _PushStatus in VERBOSE

src/Routers/FeaturesRouter.js

@@ -29,9 +29,9 @@ export class FeaturesRouter extends PromiseRouter {
           from: true,
         },
         push: {
-          immediatePush: req.config.pushController.pushIsAvailable,
+          immediatePush: req.config.hasPushSupport,
           scheduledPush: false,
-          storedPushData: req.config.pushController.pushIsAvailable,
+          storedPushData: req.config.hasPushSupport,
           pushAudiences: false,
         },
         schemas: {