Implement vulnerability archive export API

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/183521



Merged-by: Gregory Havenga <11164960-ghavenga@users.noreply.gitlab.com>
Approved-by: Schmil Monderer <smonderer@gitlab.com>
Approved-by: Brian Williams <bwilliams@gitlab.com>
Approved-by: Gregory Havenga <11164960-ghavenga@users.noreply.gitlab.com>
Approved-by: Ian Anderson <ianderson@gitlab.com>
Reviewed-by: Mehmet Emin INAC <minac@gitlab.com>
Reviewed-by: Brian Williams <bwilliams@gitlab.com>
Reviewed-by: Schmil Monderer <smonderer@gitlab.com>
Co-authored-by: Mehmet Emin INAC <minac@gitlab.com>