Separate columns for MPC submission and SSP first linking?

[mschwamb]

Thinking about commissioning or server crashes, etc could there ever be a time when submitting to the MPC and the SSP identifying the moving object might be different days? Would it be worth having discoverySubmissionDate be split into two times one that is the day SSP spotted it and one that is when SSP sent to the Minor Planet Center. This is might be over complicating things