Fixed page range for queues in failed.erb and queues.erb

Previously, the queues would show ranges that weren't quite right:

    0 to 20 of 0     #=> 0 records
    0 to 20 of 5     #=> 5 records
    20 to 40 of 25   #=> 25 records on second page

This pull request extracts that section into a partial and reports the ranges correctly in these views:
* failed.erb
* queues.erb

It also modifies the **queues.erb** view to respond to the `per_page` POST param appropriately. This way both views implement the same range and respond similarly to pagination.

##### Possible addendum
One thing I noticed that might also be worth changing is to make the **next_more.erb** partial respond to `per_page` as well, since it can respond incorrectly with some permutations of `start` and `per_page`. It seems slightly out of scope for this group though, but happy to add.