Add javadoc for entity metadata
Add javadoc for entity metadata

splunk/splunk-sdk-java,splunk/splunk-sdk-java,splunk/splunk-sdk-java,dkelmer/splunk-sdk-java,dkelmer/splunk-sdk-java,dkelmer/splunk-sdk-java,dkelmer/splunk-sdk-java,dkelmer/splunk-sdk-java,splunk/splunk-sdk-java,splunk/splunk-sdk-java,splunk/splunk-sdk-java