[ci] Remove workflow section

I don't understand why this workflow section is needed in CI. Can it be removed or what's its use?

I currently find that the docs are not triggered. They are included via https://gitlab.cern.ch/cms_tk_ph2/Ph2_ACF/-/blob/Dev/.gitlab-ci.yml?ref_type=heads#L45-L48 but validation and pages stages https://gitlab.cern.ch/cms_tk_ph2/Ph2_ACF/-/blob/Dev/.gitlab-ci.yml?ref_type=heads#L34-35 are not triggered when merge requests are created (should only run validation) or merged (should run both plus deploy), see e.g. https://gitlab.cern.ch/cms_tk_ph2/Ph2_ACF/-/pipelines/7162162 The workflow section might be the reason but it might also have other reasons.

Could you please look into this?