Make type mapping in Template Rendering addon cluster aware

Currently the type mapping which stores the template ids for each document type is stored in TemplateProcessorComponent#type2Template and therefore it is stored in the local JVM

This variable is initialized by 2 main methods:

• when a new template is created (or updated): it calls the asynchronous listener TemplateTypeBindingListener which updates the mapping in the "registerTypeMapping"
• when a new document is created: it calls the synchronous listener TemplateInitListener which will compute the mapping if it is currently null in the method TemplateProcessorComponent#getTypeMapping (note that the same method is also used in the first case to initialize the mapping before updating it)

Here we see at least 2 obvious problems:

• as the mapping is stored in the local JVM, when a new document is created, the mapping will be updated only on this node in the cluster
• as the mapping is updated asynchronously, it will be run on a worker node only, and all the portal nodes will miss the updates

A solution would be to save the type mapping in a common storage (distributed cache, KV store, etc)