Fix CAS2 template breaks permission granted to external users

Out of the box, the template shipped with the CAS2 authentication marketplace plug-in breaks the link mailed to external users granted an access.
The solution found is to add the TOKEN_AUTH plug-in to the list of authentication plug-in in the CAS2 template.

   <plugins>
        <plugin>BASIC_AUTH</plugin>
        <plugin>TOKEN_AUTH</plugin>  <!-- inserted line -->
        <plugin>CAS2_AUTH</plugin>
        <plugin>ANONYMOUS_AUTH_FOR_CAS2</plugin>
        <plugin>FORM_AUTH</plugin>
        <plugin>WEBENGINE_FORM_AUTH</plugin>
        <plugin>WEBSERVICES_AUTH</plugin>
      </plugins>

As this issue breaks a feature available by default, it is desired that the template ships a complete sample of authentication plug-ins