Pre-order the images (by position field) before storing them in ES index

[jamieu]

Currently we cap the number of multimedia elements (images) stored in the public index to 25.

However the logic that does this doesn't take into account the 'position' element' element, which means we can a random selection of 25 image rather that the first 25 (by order/position).

Also need to decide if we want up the cap to say 50?