feat(Column): added support for nested values of dataKey on Column

[simonguo]

const data = [
  {
    name: ['foo', 'bar'],
    address: { city: 'Shanghai', zipCode: '20000' }
  }
];

return (
  <Table data={data}>
    <Column>
      <HeaderCell>name</HeaderCell>
      <Cell dataKey="name.0" />
    </Column>

    <Column>
      <HeaderCell>city</HeaderCell>
      <Cell dataKey="address.city" />
    </Column>
  </Table>
);

discuss: rsuite/rsuite#2129