Adapt Web UI Jenkinsfile for all maintenance branches

With the 10.10 release, we need our pipeline file to cover this new mapping between 2.4.x elements and web 10.10.

Plus the 9.10 web ui mp job still relies on the master pipeline file which is not good as it will certainly evolve and won't be able to build the 9.10 branch at some point.

There is a need to update our Jenkinsfile in order to have web-ui-pipeline running as expected.

Syntax Reference