This commit fixes the order of the functions inside the selectPrefix
function due to the fact that, as multiple files were being uploaded,
the resetObjects function (that clears the object list) ran repeatedly
for each of these objects, right before the appendObjects function (that
appends the objects being uploaded to the current list of objects) also
ran for all of these objects. This caused all the objects in the bucket
to be repeated in the list for the number of objects that were dragged
into the dropzone.
This commit takes the existing remove bucket functionality written by
brendanashworth, integrates it to the current UI with a dropdown for
each bucket, and fixes small issues that were present, like the dropdown
not disappearing after the user clicks on 'Delete' for certain buckets.
This feature only deletes a bucket that is empty (that has no objects).
Fixes#4166
