Changes

Update the pipeline of building a build version of Silverpeas. In order
to avoid unnecessary build when no changes have been done from the last
build, a check of changes is now done. If no changes have been done in
any project, then the pipeline isn't executed. Otherwise, for each
project, no tests and no quality analysis are performed in the case the
code didn't change since the last build.

Update the build version of Silverpeas to 6.4-build240421