Add configurable wakeup delay for dnstap queues

[dalegaard]

This adds the ability to configure the wakeup delay of dnstap message queues. Previously, a static value of 1 second was used. This value is retained as the default.

This should have zero impact on any existing setup, it just gives the user the option of reducing the delay if they have a use case that could benefit from this.

Best regards, Lasse