Add search feature for quarantines and ham cache

[rjl]

When the list of items in a quarantine or ham cache is very large, it can be useful to be able to search for something specific rather than paging through the list. A search option would allow users to return a list of items that match the search criteria--a handy way to make sure that a particular e-mail you've been expecting isn't in the spam quarantine, for instance.

[rjl]

Patches by Erik Weber have been added to this ticket as a starting point.

His comments:

 There's some stuff that should be fixed in the attached patch files,
 didn't really figure out how to make pager_wrapper_db() to accept more
 prepares for the $dbparams. Also some better variable names wouldn't
 hurt  :-)

 There's two language records that I didn't create a patch file for that
 has to be added manually

 locale/en/quarantine.php:
 $lang['text_search'] = "Search for message";
 $lang['button_search'] = "Search";

 Included patch files: cache.php.diff
 themes/theme/templates/list-cache.tpl.diff

 Feel free to include it if you want.

[mortonda@…]

This patch supplied appears to take a post, and change it to a GET request - I suppose that makes it easier for paging.

Need to be more careful with the user input, to avoid injection attacks...

Also could add a select box to determine which field to search on: recipient, sender, or subject.