Add collapsible sections to job log
What does this MR do?
Additional approach to https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/25178
This generates the following (idea)
<div> that should be freely parsed by frontend:
This follows the proposal outlined here: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/25178#note_143701979
data-section contains a space delimited list of all sections in which this element is in. The section names are not sanitised, and can lead to XSS with that implementation. We should normalize section names to safe strings.
Generate a flat list of all sections with markers where they are in trace, and in what sections. This should allow frontend to generate sections and allow to collapse them hooking to