Add seen data to qa_loader

[eloquence]

#5505 will add the tables to support the seen/unseen feature in the SecureDrop Client (freedomofpress/securedrop-client#187). To test this feature, it will be helpful to have some seen annotations for submissions generated through the loader.

[eloquence]

I would suggest that all replies generated by the scripts should be marked as seen by one user, because there will never be a situation under which they are not at least seen by the sender.

[eloquence]

Given the heavy focus on SecureDrop Workstation template consolidation and the SecureDrop Core release this sprint, we've agreed to defer work on this for now during the 10/1-10/15 sprint period, likely until the next sprint. Contributor help welcome before then, though, so tagging accordingly :)

[sssoleileraaa]

Whoops closed this by saying partially resolves this issue in the pr that was merged above. Reopening because we still need to update qa_loader to show seen data (and file submissions so we can test file-specific changes, but this can be done separately if one so chooses). I updated the title and description of this issue accordingly.