Bug 11490: Split MaxItemsForBatch into 2 prefs to clarify things

Bug 11490: Split MaxItemsForBatch into 2 prefs to clarify things

Prior to this patch, a single pref (MaxItemsForBatch) was used to
restrict the use of the batch item modification and deletion.

On the batch modification tool, the pref is used to limit the number of
items a librarian is allowed to modify in a batch, but on the batch
deletion tool the pref is used to limit the number of items to display.

To clarify things, this patch split the pref into 2 new prefs:
MaxItemsToDisplayForBatchDel and MaxItemsToProcessForBatchMod.

Later we could add a MaxItemsToProcessForBatchDel if needed.
Note that this patch should not introduce any changes in the current behaviors.

Test plan:
0/ Do not execute the update DB entry
1/ Set a value != 1000 for MaxItemsForBatch
2/ Execute the update DB entry and confirm that the 2 new prefs are
initially set with the value of MaxItemsForBatch and that
MaxItemsForBatch has been deleted
3/ Set different values for these 2 prefs (2 and 3 for instance to ease
the next steps)
4/ Try to delete less than MaxItemsToDisplayForBatchDel items
=> You must see the items details
5/ Try to delete more than MaxItemsToDisplayForBatchDel items
=> You must not see the items details but are allowed to delete them
6/ Try to modify less than MaxItemsToProcessForBatchMod items
=> You must see the items details
7/ Try to modify more than MaxItemsToProcessForBatchMod items
=> You must be restricted and not allowed to process

Signed-off-by: Laurence Rault <laurence.rault@biblibre.com>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>