Adds support for PushScheduling (#3722)

* Add support for push scheduling

Add a configuration flag on the server to handle the availability of
push scheduling.

* Update push controller to skip sending only if scheduling is configured

Only skip push sending if scheduling is configured

* Update bad conventions

* Add CLI definitions for push scheduling

* Adds tests for pushTime

* Adds test for scheduling

* nits

* Test for not scheduled

src/Routers/FeaturesRouter.js

@@ -30,7 +30,7 @@ export class FeaturesRouter extends PromiseRouter {
         },
         push: {
           immediatePush: req.config.hasPushSupport,
-          scheduledPush: false,
+          scheduledPush: req.config.hasPushScheduledSupport,
           storedPushData: req.config.hasPushSupport,
           pushAudiences: false,
         },