Move JaSpell code into Solr and deprecate the factory

The JaSpell suggester is deprecated, and will be removed from the lucene codebase.  However, it's currently the default implementation for suggesters in Solr, and its Solr factory is not deprecated, so users won't have been receiving any warnings.

I suggest that we deprecate the factory, and move the relevant bits of code from lucene into Solr, as a first step.  In a follow-up we should change the default implementation (possibly by just removing the default, and forcing people to choose a factory?) and remove the deprecated code form Solr as well.