Add support for JSON_VALUE queries

[emilol]

Not all properties on a document need be mapped as columns, e.g. for Product:

public class Product
{
    public string Id { get; set; }
    public string Name { get; set; }
    public decimal Price { get; set; }

    public ProductType Type { get; set; } = ProductType.Normal;
}

The nevermore mapping could be:

public class ProductMap : DocumentMap<Product>
{
    public ProductMap()
    {
        Column(m => m.Name);
        TypeResolutionColumn(m => m.Type);
    }
}

This means that currently, if we try and query by anything other than Name or Type e.g:

var products = t.Query<Product>()
    .Where(c => c.Price == 100)
    .ToList();

We get the following error:

Error while executing SQL command in transaction 'NonParallelWorker': Invalid column name 'Price'.
The command being executed was:
SELECT Id,Name,Type,JSON
FROM [TestSchema].[Product]
WHERE ([Price] = @price)
ORDER BY [Id]

The Price field was queried as a column, instead of being parsed as part of the json payload like so:

SELECT Id,Name,Type,JSON
FROM [TestSchema].[Product]
-WHERE ([Price] = @price)
+WHERE (JSON_VALUE([JSON], '$.Price') = @price)
ORDER BY [Id]

[emilol]

@adam-mccoy just a heads up on this one; SelectAllColumnsTableResolver will return the columns as new [] { "*" }.

It's not wired in by default since the most recent release (we now use JsonLastTableColumnNameResolver which will return the column names) but this logic might need to be flipped to maintain backwards compat with the old resolver, which can still be manually wired in to the nevermore config (see example here).