Directory should provide a default caching configuration

Assign a cache to each directory

Currently if a directory is not explicitly associated to a cache : there is no cache.

Although it makes sense, in terms of performance this is not good.

We should change this logic and have something like :

• if a cache name is defined : use it
• otherwise check if <directoryname>-cache is defined
  • if yes use it
  • otherwise create it

NB : we should have a specific flag to explicitly specify the 'no-cache'

Define the default caching config

If the directory can automatically create their own cache we need to have a way to define what is the default :

• implementation class
• size
• TTL

This makes also sense to have a global "default" template that you can change so that any cache that does not explicitly define these attribute would inherit from the template.

The simplest solution seem to be to have an other extension point that allows to define a cache template, and use it as a base for merging/completing all the cache contributions.