Allow jnlp file to describe a related-content hint

If I look at my currently installed apps on the desktop almost all of
them have additional items in their program menus. They are used for:

1. Readmes
2. Help files
3. Links to homepages
4. Links to registration pages
5. Uninstalling the program

The jnlp file should be able to describe additional items as content related
to an application being installed, so desktop integration is allowed to add
these items if it deems it is safe and proper to do so.

for example:

The information-descriptor element could have added a related-content element
with href attribute and optional title, description, and icon sub-elements:

<information-descriptor>
   ...
   <related-content href="readme.html">
        <title>README</title>
        <description>The Readme file coutains a description of the contents
            of this application</description>
        <icon href="readme.jpg"/>
   </related-content>
   <related-content href="help.html">
        <title>Help</title>
        <description>The help file contains updated help information for
            this application</description>
        <icon href="help.jpg"/>
   </related-content>
   <related-content href="register.html">
        <title>Register</title>
   </related-content>
</information-desc>