Support ability to link new entities to entities which already have accessions

[aaclan-ebi]

Steps:

1. Create a submission in Ingest

   • project has BioStudies accession (accessioned outside DSP/ Ingest Archiver)
   • biomaterials have BioSamples accession (accessioned outside DSP/ Archiver)
   • project doesn't have ENA study accession
   • assay process doesn't have ENA sequencing experiment accession
   • files don't have ENA sequencing run accessions

2. Run the archiver given the submission uuid

Actual Behaviour: Unknown / Untested Archiver will probably try to archive all entities again and override the existing accessions.

Expected Behaviour: Archiver should not archive entities (project and samples) which already have accessions Archiver should archive the study, sequencing experiments, sequencing runs Archiver should identify the accessions from samples and specify that in the linking reference fields when creating sequencing experiments in the DSP

[aaclan-ebi]

I've noted that this issue is only if some entities are accessioned outside DSP and not thru the Ingest Archiver.

[aaclan-ebi]

Priority of this is not urgent as we don't have datasets blocked with this issue. I'm going to put this to icebox.