Add IRV ballot interpretations to contest-comparison report

[vteague]

Add a column for "Valid interpretations" to the report.

For each IRV ballot that is selected for audit in which either the initial upload CVR or the audit CVR is an invalid IRV preference list, add a record of the valid interpretation of that vote. (This is two separate columns). This is assuming that the main/existing column for upload cvr and audit cvr will record the raw ones.