removal of the blueocean plugin on trusted.ci and ci.jenkins.io

[Stéphane MERLE]

Hi dear contributors,

I will proceed to the removal of the blueocean plugins on both trusted.ci and ci.jenkins both may have some impact on your work. I will try to do as fast as possible.

here is the corresponding issue https://github.com/jenkins-infra/helpdesk/issues/4400

For the Jenkins infra team,

Stéphane MERLE