feat(notifications): add apple push notifications (#2077)

Author: iampaulanca

docs/reference/notification.md

@@ -2,6 +2,20 @@
 
 You can test your notification configuration by running `npm run test:notification`.
 
+## Apple Push Notification Service 
+
+| Environment variable | Description |
+|---|---|
+| `APNS_AUTHKEY` | Path to authkey on users machine |
+| `APNS_BUNDLEID` | iOS app bundle id |
+| `APNS_DEVICETOKEN` | iOS device token|
+| `APNS_KEYID` | Apple developer's key id |
+| `APNS_PRODUCTION` | true/false for production |
+| `APNS_TEAMID` | Apple developer's team id |
+
+Change your notification alert/payload/etc in apns.ts in the note object. 
+Refer to https://github.com/node-apn/node-apn for config options.
+
 ## Desktop
 
 | Environment variable | Description |