feat: Support nulls_last option in DataFrame#sort

[davidgovea]

Resolves #235

The native binding for DataFrame#sort looks like:

nodejs-polars/src/dataframe.rs

Lines 765 to 771 in 093d496

	pub fn sort(
	&self,
	by_column: String,
	descending: bool,
	nulls_last: bool,
	maintain_order: bool,
	) -> napi::Result<JsDataFrame> {

The LazyDataFrame variant also has the same shape.

---

But, the Javascript versions use a hardcoded nulls_last value of true:

nodejs-polars/polars/dataframe.ts

Line 2345 in 093d496

return wrap("sort", arg, descending, true, maintain_order);

nodejs-polars/polars/lazy/dataframe.ts

Line 965 in 093d496

return wrap("sort", arg, descending, true, maintain_order);

---

Additionally, DataFrame#sort has a minor argument bug: maintain_order is not passed when using an options object. This bug is not present in the lazy variant.

nodejs-polars/polars/dataframe.ts

Line 2337 in 093d496

return this.sort(arg.by, arg.descending);

---

So, we expose the option to the user here, and fix up the little bug.
This PR is technically breaking, since it changes the default value from nulls_last from TRUE to FALSE.
This better matches the Rust & Python versions.

[universalmind303]

Would you mind adding a test case for the nulls_last param?