Errata tool: export errata release notes

[yblock]

Create a new custom export action that narrows the exported fields to just those included in the errata release notes to speed up data processing. Fields are location, description, resolution, and error type.

[erikayvonne]

waiting on this til we upgrade wagtail

[brittanyearly]

Verified in Production.

[yblock]

had to make a minor change to which columns are exported
#1532