Support more input types for Template Rendering

Currently only 6 types are supported: https://github.com/nuxeo/nuxeo/blob/master/addons/nuxeo-template-rendering/nuxeo-template-rendering-api/src/main/java/org/nuxeo/template/api/InputType.java#L33

It would be nice to support more complex structures, as in the example below.

Implementing that would be useful to marshall the templateData property which is used when building parametrized templates.

Example of what could be supported:

• XML for templateData

  <nxdt:templateParams xmlns:nxdt="http://www.nuxeo.org/DocumentTemplate">
     <nxdt:field name="field1" type="String" value="boubou"></nxdt:field>
     <nxdt:field name="field2" type="String" value="bibi"></nxdt:field>   <nxdt:field name="field3" type="Object" value=[{key1: 'boubou', key2: 'bibi'}, {key1: 'toto', key2: 'tata'}, ...]></nxdt:field></nxdt:templateParams> 

• use in a JXLS template

  <jx:forEach items="${field3}" var="input">
  
    input.key1 | input.key2 | input.key3 | 
  
  </jx:forEach>