NodeType include attribute info in state representation

[ahonor]

Like in the Node view, the NodeType view should included the related Attributes.

Below is an example describing a NodeType that has two attributes associated.

Example output from a NodeType named "Node": https://localhost:8443/nodeType/show/1?format=xml

<nodetypes>
  <nodetype id="1" name="Node" description="An application host" image="Node.png">
    <attributes>
      <attribute id="20" name="appname" description="" filterId="1"/>
      <attribute id="21" name="environment" description="" filterId="1"/>
    </attributes> 
  </nodetype>
</nodetypes>

[orubel]

Matching Import xml for output.