Updates to ANMN_NRS_BGC harvester

* Harvest two additional tables and join them to two existing ones in the _data views.
* Simplify view definitions and standardise order of columns.
* Order all views by NRS_SAMPLE_CODE.
* Update spatial extent in metadata records.

I **think** this will run ok without deleting the existing schema, but probably best to do it anyway and start with a clean slate.