Improve Load More function of Query loop

The Query loop loadmore function could be improved in a few places. I would think about these:

1, Allow to position the button (left, middle, right, full width)

2, Allow to set how many new items the button loads (independent of the number of items displayed by default)

3, Do not display the button if there are fewer items than the number of items displayed set by default OR there are no more new items to display