Add PMIDs to submissions as well as BoW and studies

[ljwh2]

When users add PMIDs to a Body of Work, the PMID is attached to the BoW and the studies, but not to the submission. This causes multiple issues downstream, for example events are not tracked, import fails (e.g. goci#1412). In the short term we will disable the add PMID feature for users (goci#1210), but a more elegant solution would be to attach the PMID to the submission. The impact on curation workflow/prioritisation needs careful consideration.