Description

Currently, AW Fragments are rendered and stored in the Memcached object cache with the WikilambdaAbstractFragment:... keys (both with and without date).

Fragment getters and setters are spread around different parts of the stack, which complicates any evolution of our Fragment storage layer.

Let's put a bit of work on isolating AWFragment storage now that we are building AWArticle Storage.

AWFragmentStore will surface two methods: a setter and a getter, which internally will do the same as we do now (calling MemcachedWrapper getters and setters)