Changes

Add a new Jenkinsfile to release versions of the project Silverpeas Kernel

Take into account of the new location and new major version of our Nexus service

Java 11 isn't anymore supported by SonarCloud. Use a property to indicate we force the analyse with a deprecated Java version

Update the build of the Docker image for a build environment for
Silverpeas projects. First, a new build argument is passed: the version
of Java to use for running a Sonar analysis. Second, in order to build
a fix version of an existing Docker image stable version, we reorder the
pipeline stages so that the release of a stable version is done after
its build.

Update the pipeline for building a build version of Silverpeas: Sonar is
now executed by using at least Java 17. This version of Java is provided
by the Docker image through the env var SONAR_JDK_HOME.

The Docker image version for Silverpeas 6.3.x is now 6.3.3

Refine the release pipeline of Silverpeas Kernel by adding a Sonar analysis before effectively releasing the new version