feat(node): parse arrow types in alterColumns() (#2208)

Previously, users could only specify new data types in `alterColumns` as
strings:

```ts
await tbl.alterColumns([
  path: "price",
  dataType: "float"
]);
```

But this has some problems:

1. It wasn't clear what were valid types
2. It was impossible to specify nested types, like lists and vector
columns.

This PR changes it to take an Arrow data type, similar to how the Python
API works. This allows casting vector types:

```ts
await tbl.alterColumns([
  {
    path: "vector",
    dataType: new arrow.FixedSizeList(
      2,
      new arrow.Field("item", new arrow.Float16(), false),
    ),
  },
]);
```

Closes #2185

docs/src/guides/tables.md

@@ -942,6 +942,28 @@ rewriting the column, which can be a heavy operation.
     ```
     **API Reference:** [lancedb.Table.alterColumns](../js/classes/Table.md/#altercolumns)
 
+You can even cast the a vector column to a different dimension:
+
+=== "Python"
+
+    === "Sync API"
+
+        ```python
+        --8<-- "python/python/tests/docs/test_guide_tables.py:import-pyarrow"
+        --8<-- "python/python/tests/docs/test_basic.py:alter_columns_vector"
+        ```
+    === "Async API"
+
+        ```python
+        --8<-- "python/python/tests/docs/test_guide_tables.py:import-pyarrow"
+        --8<-- "python/python/tests/docs/test_basic.py:alter_columns_async_vector"
+        ```
+=== "Typescript"
+
+    ```typescript
+    --8<-- "nodejs/examples/basic.test.ts:alter_columns_vector"
+    ```
+
 ### Dropping columns
 
 You can drop columns from the table with the `drop_columns` method. This will

docs/src/js/interfaces/ColumnAlteration.md

@@ -16,7 +16,7 @@ must be provided.
 ### dataType?
 
 ```ts
-optional dataType: string;
+optional dataType: string | DataType<Type, any>;
 ```
 
 A new data type for the column. If not provided then the data type will not be changed.