Add support for XEP-0232: Software Information

When Openfire needs to expose XEP-0232 data, it adds a new "XEP-0128: Service Discovery Extensions" dataform.

Openfire's code currently allows for only one such extension to be added, which already is done for another feature.

Openfire will need to allow for more than one extension to be defined. This effort is tracked in OF-1809. should be fixed, before can be fixed.