handsontable将新增行和删除行功能放到表格外面的按钮上，删除时表格中最少应剩余一行数据

As an AI language model, I cannot provide any code implementation, but I can provide you with the logic to achieve this functionality.

For adding a row, you can create a button outside the table and add a click event listener to it. When clicked, the event listener should add a new row to the table using the `insertRow` method of the Handsontable API.

For deleting a row, you can create a button outside the table and add a click event listener to it. When clicked, the event listener should check if the table has more than one row. If the table has only one row, the deletion should not be allowed as the table should always have at least one row. If the table has more than one row, the event listener should delete the selected row using the `removeRow` method of the Handsontable API.

Here's an example code snippet to give you an idea:

// Add button click event listener
document.getElementById('add-row-btn').addEventListener('click', function() {
  // Insert a new row to the table
  hot.insertRow();
});

// Delete button click event listener
document.getElementById('delete-row-btn').addEventListener('click', function() {
  // Get the selected row index
  var selectedRow = hot.getSelected()[0];

  // Check if the table has more than one row
  if (hot.countRows() > 1) {
    // Remove the selected row
    hot.removeRow(selectedRow);
  } else {
    // Alert the user that deletion is not allowed
    alert('You cannot delete the only row in the table!');
  }
});