Catalog-level CSV tableStyle

[stevage]

It would solve a few problems if in an init file could define column names that would be styled in a certain way for any CSV file dropped in, across a whole catalog. That is, something like:

{
    "catalog": [ 
       "..."
    ],
    "columnStyles": [{
        "columnRegex": ".*_change$",
        "tableStyle": {
            "colorMap": [ 
                {
                    "value": "-10",
                    "color": "red",
                }, {
                    "value": "0",
                    "color": "white",
                }, {
                    "value": "10",
                    "color": "blue"
                }
            ]
        }
    }, {
        "columnRegex": "^Party$",
        "tableStyle": {
            "colorMap": [ 
                {
                    "value": "ALP",
                    "color": "hsl(20,80%,60%)",
                }, {
                    "value": "LNP",
                    "color": "hsl(250, 80%, 60%)",
                }, {
                    "value": null,
                    "color": "grey" // applied to "other" values
                }
            ]
        }
    }
    ]
}

Benefits:

• Catalog managers can define colour schemes that will work for any conformant CSV files dropped in.
• Less repetitive than defining colour schemes for every CSV file in a catalog
• More flexible (and greater scope for domain-specificity) than us defining rules like this that apply in every TerriaJS instance
• Opens up the intriguing possibility of catalog files that just contain styles, so "nationalmap.gov.au#electoral" could be just styles for CSVs that you're about to drop in.
• Probably solves the actual problem behind the request for per-row colours, and keeps presentation metadata out of the CSV.