Changes

Improve the pipeline of publishing the community web site by taking into
account the release of a new version of Silverpeas.

The pipeline of publishing the documentation of Silverpeas-Core,
Silverpeas-Components and the community web site for a new version of
Silverpeas is now in declarative syntax and has been improved to take
into account existing Jenkins job (for delegating some of its stages)

The pipeline of releasing a new version of Silverpeas takes care now of
the expectations of the pipeline of publishing Silverpeas projects'
documentation.