Add auto configuration support for Spring Data Solr.

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.