Add SLA pausing, SLA reports, SLA filtering and kanban SLA state (phase 3)

Statuses can be flagged to pause the resolution clock; sla_history records the intervals a ticket's clock actually ran and the deadline is re-based on remaining budget when it resumes. Adds SLA Summary and SLA by Client reports, an SLA state filter on the ticket list, SLA colouring on kanban cards, and an Urgent column on the Tickets by Client report. DB update 2.5.1. Also fixes resolution SLA verdicts being skipped when resolving via kanban or the client portal.

cron/ticket_email_parser.php

@@ -370,6 +370,7 @@ function addReply($from_email, $date, $subject, $ticket_number, $message, $attac
         }
 
         mysqli_query($mysqli, "UPDATE tickets SET ticket_status = 2, ticket_resolved_at = NULL WHERE ticket_id = $ticket_id AND ticket_client_id = $client_id LIMIT 1");
+        resetTicketResolutionSla($ticket_id);
 
         logAudit("Ticket", "Edit", "Email parser: Client contact $from_email_esc updated ticket $config_ticket_prefix$ticket_number_esc ($subject)", $client_id, $ticket_id);
         triggerCustomAction('ticket_reply_client', $ticket_id);