Solr indexer improve

1. Update SolrIndexer.java to enable parse and index user defined fields.
fields configuration are read from:
fcrepo-jms-indexer-webapp/src/main/resources/solrIndexerFieldsConfig.txt
2. Test SolrIndexerTest.java is updated and read fields configuration from:
fcrepo-jms-indexer-core/src/test/resources/solr/solrIndexerFieldsConfig.txt
Config file for embedded solr server for testing is updated to index fields defined in file above:
fcrepo-jms-indexer-core/src/test/resources/solr/conf/schema.xml
3. SolrIndexerIT.java is deleted since it did the same testing as SolrIndexerTest.java above but reading configuration from Spring xml.
Short documents are at wiki:
https://wiki.duraspace.org/display/FF/Solr+Indexer+Setup
https://wiki.duraspace.org/display/FF/SolrQueryRecipes