Allow automated and airtight setup

[FireBurn]

This respects envirnmental variables and uses locally downloaded datafiles if present

[FireBurn]

Sorry to "at" you @cblanc but you approved my other PR and I was wondering if this request was OK too?

[cblanc]

Hi @FireBurn - sorry I didn't follow up on this. The latest major update does away bin scripts and relies on standing up the dataset through docker https://github.com/ideal-postcodes/postcodes.io/blob/main/Dockerfile.pg

If you need to incorporate into pg, the pg_dump will always be linked out here: https://github.com/ideal-postcodes/postcodes.io/blob/main/latest

The most recent update however has substantially modified the schemas. Tables have been thoroughly denormalised