Registers required components in application context if not available to
set up environment for usage with Spring Data Solr. Will listen on
SolrServer and SolrRepositories for configuration.
By default an HttpSolrServer is registered unless a zkHost (zookeeper
host) is defined. In that case an instance of CloudSolrServer will be
created.
By default multicore support is enabled, creating instances of
SolrServer for each core defined via @SolrDocument.
Andy Wilkinson
Christoph Strobl