new: usr: Implement the min-transfer-rate-in configuration option

A new option 'min-transfer-rate-in <bytes> <minutes>' has been added
to the view and zone configurations. It can abort incoming zone
transfers which run very slowly due to network related issues, for
example. The default value is set to 10240 bytes in 5 minutes.

Closes #3914

Merge branch '3914-detect-and-restart-stalled-zone-transfers' into 'main'

See merge request isc-projects/bind9!9098