Allow more array types for SQLite #941

The way we store arrays in SQLite is by converting the values to JSON strings, and then storing them in a text field.

We have this function which converts list values into JSON:

We validate the types here to make sure we can serialise it.

The list of types is fairly limited - it excludes Decimal, date, and datetime, because Python's json.dumps is pretty restrictive. We might be able to extend json.dumps to handle these additional types.

Note - if orjson is installed, this is less of a problem, as it serialises far more types.