Share performance indicators partials and shortcodes
Security is moving Performance Indicators to the internal handbook.
The partials and shortcodes are different from the public handbook, so
there's a need to harmonize the two with a common ground.
Warning: layouts/partials/performance-indicators/chart.html
is overriden in this MR with the version from the public handbook. This other version seems to be more up-to-date but there could be some side effects I haven't spotted.
refs https://gitlab.com/gitlab-com/gl-security/security-department-meta/-/issues/1685
Edited by Philippe Lafoucrière