formatter: format record with no record ID

* Adds back support of the case where BibFormatObject also
  can support to work with records without any record ID.

Co-authored-by: Jan Aage Lavik <jan.age.lavik@cern.ch>
Co-authored-by: Guillaume Lastecoueres <guillaume.lastecoueres@cern.ch>
Signed-off-by: Jan Aage Lavik <jan.age.lavik@cern.ch>