web: group targets by job then instance (#4898)
web: group targets by job then instance (#4898)

Signed-off-by: Simon Pasquier <38e2d22e48be18381a59028f88390cad04670376@redhat.com>
GoogleCloudPlatform/prometheus,GoogleCloudPlatform/prometheus,alileza/prometheus,GoogleCloudPlatform/prometheus,prometheus/prometheus,prometheus/prometheus,alileza/prometheus,kangwoo/prometheus,prometheus/prometheus,alileza/prometheus,Gouthamve/prometheus,Gouthamve/prometheus,kangwoo/prometheus,GoogleCloudPlatform/prometheus,kangwoo/prometheus,Gouthamve/prometheus,prometheus/prometheus,keegancsmith/prometheus,prometheus/prometheus,keegancsmith/prometheus,keegancsmith/prometheus,Gouthamve/prometheus,keegancsmith/prometheus,alileza/prometheus,keegancsmith/prometheus,kangwoo/prometheus,GoogleCloudPlatform/prometheus,alileza/prometheus