Merge branch '421915-rest-endpoints-group-ca' into 'master'

REST get, post and delete endpoints for SSH Certificates

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/130866



Merged-by: Michał Zając <mzajac@gitlab.com>
Approved-by: Roy Zwambag <rzwambag@gitlab.com>
Approved-by: mo khan <mo@mokhan.ca>
Approved-by: João Pereira <jpereira@gitlab.com>
Approved-by: Michał Zając <mzajac@gitlab.com>
Reviewed-by: Amy Qualls <aqualls@gitlab.com>
Reviewed-by: mo khan <mo@mokhan.ca>
Co-authored-by: ghinfey <“ghinfey@gitlab.com”>