Procedure to setup Firebase configuration in plugin admin area

Following is procedure to setup Firebase configuration in plugin admin area to send free push notification across multiple devices
Configure Firebase settings as per below steps in plugin admin area,
1. Sign in to Firebase, then open your project, click settings icon & select Project settings

= To get Firebase server key (for field 1 in admin firebase settings) =
2. project settings > cloud messaging tab > get server key or click on add server key button to get server key

= To get Firebase config fields (for fields 2 to 8 in admin firebase settings) =
3.If you do not have web app, Create a new web app. After creating a new app, it will show firebase config fields
Project settings > General under your apps section > click on config button to view configuration fields

= To get Firebase public key (for field 9 in admin firebase settings) =
4. Open the Cloud Messaging tab of the Firebase console Settings pane and scroll to the Web configuration section.
In the Web Push certificates tab, click Generate Key Pair. The console displays a notice that the key pair was generated, and displays the public key string and date added.
(If you already Generated key pair then no need to generate it again)`