Support for Live Data in Velocity

It is now possible to insert a Live Data using scripting instead of using the usual liveData macro.

Example using Velocity:

$services.liveData.render({
  'id': 'users',
  'properties': '_avatar,doc.name,first_name,last_name',
  'source': 'liveTable',
  'sourceParameters': 'className=XWiki.XWikiUsers&translationPrefix=xe.userdirectory.'
})