feat: add audit reports

[jaypaik]

Formatting the audit report file names as:
[short commit hash at which audit was conducted]_[ISO date of report delivery]_[vendor].pdf
[ISO date of report delivery]_[vendor]_[short commit hash at which audit was conducted].pdf

[adam-alchemy]

Nit: imo, we can leave the commit hash until the end, because the date and vendor are more important fields. So we could instead format the name as [ISO date of report delivery]_[vendor]_[short commit hash].pdf

[jaypaik]

Nit: imo, we can leave the commit hash until the end, because the date and vendor are more important fields. So we could instead format the name as [ISO date of report delivery]_[vendor]_[short commit hash].pdf

Agreed re: importance. I sort of like the property of having audits conducted on the same commit clearly grouped together when ordered by filename (audit reports against the same commit may be delivered in different days). But a temporal ordering is nice, and 99% time they will be grouped the same way, so I'll change it!