Feature Request: Ticket metric reporting

[wrongecho]

On the back of #225 - "Add more to reporting (Average Response and Resolution Time, Service Requests, Ticket satisfaction)"

• Ticket counts (e.g. X tickets opened this month)
• Average response time (need to determine if a "response" is a ticket being assigned or replied to)
• Average resolution time
• Ticket satisfaction stats
  • We already have the ticket satisfaction smiley/sad faces - with notifications issued if a sad face is selected. Possibly we should limit the ability to give feedback to ~30 days after the ticket is closed?
• Ticket counts by priority and category

[wrongecho]

Halfway there

[wrongecho]

I think we need to add a 'ticket_first_response_at' field to ticketing to make this achievable, otherwise we're having to parse every single reply each time report loads. This also makes any sort of first response SLA MUCH more realistic.
This could be automatically be set when a reply is added to a ticket. If null, we could add a visual cue to a ticket to show the first response is outstanding (red asterisk)?