SchemaCodecFactory should be the implicit default if no <codeFactory/> is configured

Solr has a SchemaCodecFactory that enables may Solr FieldType impls to customize the behavior of of the indexing codec – but unless it is explicitly configured in solrconfig.xml, the Lucene Codec.getDefault() is used in it's place.

We should consider changing the behavior of Solr so that the implicit <codecFactory/> is SchemaCodecFactory, and offer a (new) LuceneDefaultCodecFactory that users can configure if there have any strong reason for not wanting to support the per-field configurability of SchemaCodecFactory