Reference maturity matrix from FAQ

This reverts commit 693ddaf and updates 'model' to matrix

docs/src/main/asciidoc/extension-faq.adoc

@@ -19,8 +19,8 @@ The document header ends at the first blank line. Do not remove the blank line b
 ### Why would I want to write an extension?
 
 See the xref:writing-extensions#extension-philosophy[extension philosophy].
-
-One useful thing extensions can do is bundle other extensions.
+The xref:extension-maturity-matrix[extension maturity matrix] shows the kinds of capabilities extensions can offer.
+Another useful thing extensions can do is bundle other extensions.
 Have a look at the link:https://quarkus.io/extensions/io.quarkiverse.microprofile/quarkus-microprofile/[Quarkus MicroProfile extension] for an example of aggregator extensions.
 
 ### Are there cases an extension isn't necessary?
@@ -30,6 +30,11 @@ Not every problem needs an extension!
  For example, plain libraries can create new configuration elements and register classes with Jandex (this link:https://www.loicmathieu.fr/wordpress/en/informatique/quarkus-tip-comment-ne-pas-creer-une-extension-quarkus/[blog shows how]).
 
 
+## How do I know what kind of capabilities I might want to include in an extension?
+
+Have a look at the xref:extension-maturity-matrix[extension maturity matrix].
+
+
 ## Bytecode transformation
 
 ### How can I change the code of things on the classpath?