[KARAF-3231] Release Apache Karaf 2.4.0. Update website

git-svn-id: https://svn.apache.org/repos/asf/karaf/site/trunk@1626471 13f79535-47bb-0310-9956-ffa450edef68
[KARAF-3231] Release Apache Karaf 2.4.0. Update website

git-svn-id: https://svn.apache.org/repos/asf/karaf/site/trunk@1626475 13f79535-47bb-0310-9956-ffa450edef68