Add Joomla! repositories

This adds stable Joomla! Framework components with direct dependencies to Symfony components, an additional joomla.org website using Symfony components, and adds comments noting where the dependencies come from

Author: mbabker

projects/joomla.yml

@@ -1,8 +1,14 @@
 name: Joomla!
-url: http://www.joomla.org/
+url: https://www.joomla.org/
 dependencies:
+    # Joomla! CMS
     - https://github.com/joomla/joomla-cms/blob/staging/composer.json
+    # joomla.org websites
     - https://github.com/joomla/framework.joomla.org/blob/master/composer.json
+    - https://github.com/joomla/jissues/blob/master/composer.json
+    # Joomla! Framework components
+    - https://github.com/joomla-framework/crypt/blob/master/composer.json
+    - https://github.com/joomla-framework/registry/blob/master/composer.json
 description: |
     Joomla is an award-winning content management system (CMS), which
     enables you to build Web sites and powerful online applications. Many