Remove sonarqube

Gitlab CI cannot be used on sonarqube CE any more.

.gitlab-ci.yml

@@ -12,8 +12,7 @@ test:
     - docker
   script:
     - (cd acme4j-it; mvn -B docker:remove)
-    - mvn -B -P ci org.jacoco:jacoco-maven-plugin:0.8.3:prepare-agent verify
-    - mvn -B sonar:sonar -Dsonar.gitlab.commit_sha=$CI_BUILD_REF -Dsonar.gitlab.ref_name=$CI_BUILD_REF_NAME
+    - mvn -B -P ci verify
 
 deploy:
   tags:

acme4j-example/pom.xml

@@ -30,7 +30,6 @@
 
     <properties>
         <!-- I prefer readability over maintainability in the examples... -->
-        <sonar.skip>true</sonar.skip>
         <spotbugs.skip>true</spotbugs.skip>
     </properties>
 

acme4j-it/pom.xml

@@ -32,7 +32,6 @@
         <pebble.version>latest</pebble.version>
 
         <skipITs>true</skipITs>
-        <sonar.coverage.exclusions>src/main/java/org/shredzone/acme4j/**</sonar.coverage.exclusions>
     </properties>
 
     <profiles>