[TENE-650] In solr we only have documents with body_nolang
Add RecordOcrBodyFieldType
enum. Remove SOLR_CONTENT_FIELD_NAME
variable. Change the fetching of the record's body content, based on the existing body field in it. Change the record body update based on the Language_attr field. Change how language is retrieved from xml record in LanguageExtractor. Update LanguageExtractorTest. Add Lanugage_attr field to fbc2dlibrasolr.xsl.