Add missing data for Australia Post Locations

[mwu2018]

v7 has the locations https://nationalmap.gov.au/#share=s-rkIRSdYPsG2oVAfyVsYx9dZK2sA but v8 has not https://beta.nationalmap.terria.io/#share=s-bW14yxPc9mA1UEItXsh4PIR60LA

Tech Node

            {
              "type": "csv",
              "name": "Australia Post Locations",
              "url": "data/auspost-locations.csv",
              "activeStyle": "State",
              "id": "YUeesYKH",
              "shareKeys": [
                "Root Group/National Datasets/Habitation/Australia Post Locations"
              ]
            }

Options

1. Copy from https://github.com/TerriaJS/nationalmap/blob/master/wwwroot/data/auspost-locations.csv to https://github.com/TerriaJS/terrace/tree/master/wwwroot/data
2. Change url reference to https://tiles.terria.io/static/auspost-locations.csv

Option 2 is preferred as we don't need to keep a local copy of data.