Helper to copy Vec<u8> to Uint8Array

[kylebarron]

I.e. each public binding should be able to change from

parquet-wasm/src/arrow1/wasm.rs

Lines 5 to 19 in bfd6943

	pub fn read_parquet(parquet_file: &[u8]) -> Result<Uint8Array, JsValue> {
	let buffer = match crate::arrow1::reader::read_parquet(parquet_file) {
	// This function would return a rust vec that would be copied to a Uint8Array here
	Ok(buffer) => buffer,
	Err(error) => return Err(JsValue::from_str(format!("{}", error).as_str())),
	};
	let return_len = match (buffer.len() as usize).try_into() {
	Ok(return_len) => return_len,
	Err(error) => return Err(JsValue::from_str(format!("{}", error).as_str())),
	};
	let return_vec = Uint8Array::new_with_length(return_len);
	return_vec.copy_from(&buffer);
	return Ok(return_vec);
	}

to

pub fn read_parquet(parquet_file: &[u8]) -> Result<Uint8Array, JsValue> {
    let buffer = crate::arrow1::reader::read_parquet(parquet_file)?;
    Ok(crate::utils::copy_vec_to_uint8array(buffer))
}

Should be some way to make the ? work in this context? You might need to add an impl for converting from the ParquetError to a js Error?