SLING-3776 JsonRendererServlet should provide a way to list children as ...

Adding an "array" selector will print the children of the node under the key "_children" and adds its key as a "_name" attribute. The wordings would need to be improved.

I did the implementation of it only in the servlet, some parts may be possible to be moved to JSONObject though imho I think it belongs rather to the servlet because it is for pure formatting.