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/email-composer/index.ts

@@ -116,7 +116,9 @@ export interface EmailComposerOptions {
   repo: 'https://github.com/katzer/cordova-plugin-email-composer',
   platforms: ['Amazon Fire OS', 'Android', 'Browser', 'iOS', 'Windows', 'macOS']
 })
-@Injectable()
+@Injectable({
+  providedIn: 'root'
+})
 export class EmailComposer extends IonicNativePlugin {
   /**
    * Checks if the app has a permission to access email accounts information