ContentDefinitions: Support list properties

Description

Optimizely Content Cloud added support for list properties (including for blocks). You can define list properties through ContentDefinitions API also.

To define a list property then dataType should be set to PropertyCollection and itemType to the type of items within the list. 

Example of a property definition to create of a list of blocks. Here the blockType given as itemType must be an existing blockType (or part of same manifest) within CMS.

{                
   "name": "BlockList",                
   "dataType": "PropertyCollection",                
   "itemType": "InlineBlock"            
}

Or for example to define a list of Urls

{                
  "name": "UrlList",                
  "dataType": "PropertyCollection",                
  "itemType": "PropertyUrl"            
}