TPC-DS schemas are not 100% to spec (typos, etc.)

[mwc360]

1. store table: the spec is "s_tax_percentage" but this package generates "s_tax_precentage"
2. customer table: the spec is "c_last_review_date**_sk**" as an Identity column which maps to an integer but this package generates "c_last_review_date" (_sk is missing) as a string.

I propose that it's better to fix these schema issues instead of continuing to generate data that is incompatible (w/o modification) with TPC-DS generated queries.

I'd happy to submit the PR but want a thumbs up before doing so, based on the PRs submitted YTD I'm not sure if this project is still being maintained.