Move to immutable/blockchain tables

[faggion]

Hi, Connor

Thank you for this great tool.

Considering that the audit tables shouldn't be updated, I wonder if it would be a good improvement to change the tables to "immutable" (blockchain maybe?) with "don't drop until" / "don't delete until" options in the generator.

[connormcd]

Valid point, but two things

1. its pretty selective because it limits the usage to 19.10 or greater
2. that does introduce the potential of performance overheads because we don't know if people will use the audit facility for OLTP versus batch style operations.
   But I'll look at factoring it in as an option.