Bug 21890: Add can_any_reset_password() to the Categories TT plugin

Bug 21890: Add can_any_reset_password() to the Categories TT plugin

This patch introduces a method to the Koha::Template::Plugin::Categories
TT plugin. This methods queries for categories filtering them by
effective_reset_password flag set, and returns a boolean representing the fact
that there's at least one category allowed.

To test:
- Apply this patch
- Run:
  $ kshell
 k$ prove t/db_dependent/Template/Plugin/Categories.t
=> SUCCESS: Tests pass!
- Sign off :-D

Caveat: this patch/tests require the schema to be updated

Signed-off-by: Liz Rea <wizzyrea@gmail.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>