refactor: optimize plugins for angular treeshaking

BREAKING CHANGE: You can remove the plugin import from the app.module.ts because of the changed Inject decorator

src/@ionic-native/plugins/sms/index.ts

@@ -50,7 +50,9 @@ export interface SmsOptionsAndroid {
   repo: 'https://github.com/cordova-sms/cordova-sms-plugin',
   platforms: ['Android', 'iOS', 'Windows', 'Windows Phone 8']
 })
-@Injectable()
+@Injectable({
+  providedIn: 'root'
+})
 export class SMS extends IonicNativePlugin {
   /**
    * Sends sms to a number