Bug 9448: Add separate permission for writing off fees

Bug 9448: Add separate permission for writing off fees

Adds new sub-permissions to updatecharges, 'writeoff' for writing off
fees and 'remaining_permissions' for all other fee related activites.

Test plan:
1) Apply patch
2) Run updatedatabase.pl
3) Remove the 'writeoff' permission from your privileges
4) Attempt to write off a fee, you should not be able to
5) Re-add the 'writeoff' permission
6) Attempt to write off a fee, you should now be able to do so

Signed-off-by: Joel Sasse <jsasse@plumcreeklibrary.net>
Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>