Add known exploited column to CyHy customer report csv attachments

[chelsgr]

Task

In support of BOD 22-01 requirement 7, add “known exploited” column to these attachments on the CyHy customer reports:

• findings.csv
• recently-detected.csv

References

• Epic https://github.com/cisagov/cool-system-internal/issues/107
• Story https://github.com/cisagov/cyhy-reports/issues/68
• Current Estimated LOE: estimated 4 hours for this task.

[dav3r]

Resolved via https://github.com/cisagov/cyhy-reports/pull/72.