Merge branch '467194-ci-taggings-model' into 'master'

Introduce Ci::Taggings model

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/159898



Merged-by: Omar Qunsul <oqunsul@gitlab.com>
Approved-by: Tianwen Chen <tchen@gitlab.com>
Approved-by: Omar Qunsul <oqunsul@gitlab.com>
Reviewed-by: Tianwen Chen <tchen@gitlab.com>
Co-authored-by: Marius Bobin <mbobin@gitlab.com>