Allow for duplicate tickets

osTicket uses message-id to detect previously "seen" emails in order to prevent duplicate tickets from being created from a single email. This is necessary to avoid duplicate tickets when fetched emails are left in the
INBOX.

The proposal will allows for less strict matching which can allow for duplicate tickets when an email is sent to multiple email queues.

__Use Case Scenario__:
 * We have multiple departments with strict access control on tickets
  e.g members of Billing department do not have access to tickets in Legal department
 * Joe sends an email to billing@company.com and legal@company.com (CC)
 * If a ticket gets created in Legal first (unpredictable - depends on which inbox gets processed first)
  - Billing department will be left in the dark
  - No way for legal to know that the same email was also addressed to Billing

====
- [ ] Add setting to enable/disable the strict mode.
- [ ] Log internal notes on duplicate tickets (?)