Use ICUCollationField for sorting instead of TextField

Rather than specifying an analyzer within <fieldtype …​ class="solr.TextField">, the solr.CollationField and solr.ICUCollationField field type classes provide this functionality. solr.ICUCollationField, which is backed by the ICU4J library, provides more flexible configuration, has more locales, is significantly faster, and requires less memory and less index space, since its keys are smaller than those produced by the JDK implementation that backs solr.CollationField.

solr.ICUCollationField is included in the Solr analysis-extras contrib - see solr/contrib/analysis-extras/README.txt for instructions on which jars you need to add to your SOLR_HOME/lib in order to use it.