feat!: replace dgeni/gulp with TypeDoc for README generation

Replace the legacy dgeni/gulp documentation pipeline with TypeDoc
and typedoc-plugin-markdown. Generates plugin README files with
extracted @Plugin() decorator metadata. Register custom JSDoc tags
used by plugin source files.

docs/plugins/firebase-analytics/README.md

@@ -1,12 +1,5 @@
 # Firebase Analytics
 
-  <p style="color:orange">
-    This plugin is still in beta stage and may not work as expected. Please
-    submit any issues to the <a target="_blank"
-    href="/issues">plugin repo</a>.
-  </p>
-
-
 ```
 $ ionic cordova plugin add cordova-plugin-firebase-analytics
 $ npm install @awesome-cordova-plugins/firebase-analytics
@@ -41,7 +34,5 @@ And in the same file, you'll have to add `xmlns:tools="http://schemas.android.co
 ## Supported platforms
 
 - Android
-  - iOS
-  
-
+- iOS