Bug 25682: Style transfers interface to match checkin page

Bug 25682: Style transfers interface to match checkin page

This patch updates the transfer page to make it better match the style
of the checkin page. The static dialog is converted to a modal for
consistency's sake, with information displaying as similarly as
possible to the checkin page. The library dropdown is now styled with
Select2.

To test, apply the patch and go to Circulation -> Transfers.

- Test some simple transfers: Items which are not checked out, some
  which are checked out.
- Test that the page's handling of items on hold matches current master
  (i.e. broken, see Bug 36686). Description of current behavior:

- Logged in to Branch A.
- Find a barcode for a title which has a biblio-level
  hold (not already in transit) to be sent to Branch B.

  - Submit transfer to Branch C.
    - Three actions are offered:
      1. Transfer to Branch B
      2. Cancel hold and then attempt transfer
      3. Ignore and return to transfers

      Testing each of the three actions:
          1. The page says "Item is now in transit
             to Branch C (not the hold's destination)"
          2. The item is not in transit, and the hold
             has been changed to an item-level hold.
          3. Works correctly. No change to the hold
             and no transfer initiated.

- Logged in to Branch A.
- Find a barcode for a title which has a biblio-level
  hold (not already in transit) to be sent to Branch B.
  - Check in the item, confirm hold and transfer.

  - Submit transfer to Branch C.
    - Two actions are offered:
      1. Cancel hold and then attempt transfer
      2. Ignore and return to transfers

      Testing each of the two actions:
          1. The page says "Reserve cancelled" (sic).
             The original transfer to Branch B is still
             in place.
          2. Works correctly. No change to the hold and
             the original transfer remains.

- Logged in to Branch D.
- Find a barcode for a title which has a biblio-level
  hold (not already in transit) to be held at Branch D.
  - Check in the item, confirm hold.

- Log in to Branch A.
  - Submit a transfer with that barcode to Branch C.
    - Two actions are offered:
      1. Cancel hold and then attempt transfer
      2. Ignore and return to transfer.

      Testing each of the two actions:
          1. The page says "Reserve cancelled" (sic).
             The hold has been cancelled but the item
             has not been transferred.
          2. Works correctly. Hold remains unchanged,
             no transfer initiated.

Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>