Ignore certain mails from processing based on email subject

Summary

At the moment, every email which is received by the email account associated to the SD mail handler will be created as a request if possible.

Some organizations have a phone number to be contacted by and when a call is missed, an email will be sent. This email will always be of the same Subject. If the email is sent to the SD mail, it will create a request which doesn't contain any information.

Suggestion

Allow admins to configure a string in SD for email subjects to be ignored.

The Mail handler will compare this string to the subject of all mails and if it matches, the email will be ignored.