Bug 7791: (follow-up) add warning after deletion if some records were not deleted

Bug 7791: (follow-up) add warning after deletion if some records were not deleted

This followup add some warnings after deletion if some items were not
deleted.

4 types of messages are possible :
- x item(s) attached.
- x subscription(s) attached.
- x order(s) attached.
- Unknown error.

To test :
test a
1. create a basket with
- an order using a record A which has already an item, which is used in
   a subscription, and in other order (in an other basket)
- an order using a record B used nowhere elese
2. click on "Delete basket"
3. choose button "Delete basket, orders and records"
4. you should see a page anouncing basket deletion, and that record A was
   not deleted because of its item, subscription and order.
5. check the link around the title of record B takes you to the record
6. check the link under the warning box ("Click here to go back to
   booksellers page") takes you to booksellers page
5. check record B is deleted

test b
1. suppress the subscription linked with record A
2. create an other basket using record A
3. delete the basket on the same way as for test a
4. you should see a page anouncing basket deletion, and that record A was
   not deleted because of its item and order

test c
1. suppress the item attached under record A
2. create an other basket using record A
3. delete the basket on the same way as for test a
4. you should see a page anouncing basket deletion, and that record A
   was not deleted because of its orderBug 7791 Followup: add warning
    after deletion if some records were not deleted

Signed-off-by: Chris Cormack <chris@bigballofwax.co.nz>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>