WIP solr7 update

* deleted the chatpal backend #289
* updated Solr Version to `7.5.0` #248
* started to update Solr configurations for the new Solr Version #248
* started to adapt the ConversationInterestingTermsExtractor so that it works with multiple clients (will replace the Systel Crawl Solr index) #290

application/pom.xml

@@ -539,13 +539,6 @@
                                     <classifier>solrcores</classifier>
                                     <type>zip</type>
                                 </artifactItem>
-                                <artifactItem>
-                                    <groupId>${project.groupId}</groupId>
-                                    <artifactId>chatpal-index</artifactId>
-                                    <version>${project.version}</version>
-                                    <classifier>solrcores</classifier>
-                                    <type>zip</type>
-                                </artifactItem>
                             </artifactItems>
                         </configuration>
                     </execution>

application/src/main/resources/application.properties

@@ -54,8 +54,9 @@ endpoints.metrics.enabled=false
 ##Analysis configuration
 
 ##Analysis pipeline
-#deactivate the interesting terms from previous conversations
-smarti.analysis.pipeline.optional=*,!keyword.interestingterms.conversation
+#interesting terms from previous conversations is no longer deactivated as
+#we do now have sufficient data in the conversation index
+#smarti.analysis.pipeline.optional=*,!keyword.interestingterms.conversation
 
 ##Conversation Language configuration
 #Set German as language for the conversations