Merge topic 'ci-reorg'

cc1f631e38 ci: Cover compilation with Clang on Fedora in every merge request
5ccf55ffa7 ci: Decouple Fedora+Clang common job settings from external testing
126e787846 ci: Convert Fedora+Ninja-Multi-Config job to common conventions

Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !11597