Merge pull request #65 from atlasapi/mbst-3937-pa-biogs

Persistence of new fields for PA Biogs ingest
add id field to ChildRef
always persist numeric id
resolve container summaries with ids
persist numeric ids in child and parent refs
Merge branch 'mbst-4003-id-childRefs' into stage

* mbst-4003-id-childRefs:
  persist numeric ids in child and parent refs
  resolve container summaries with ids
  always persist numeric id
  add id field to ChildRef