chg: dev: Separate the connect and the read TCP timeouts in dispatch

The network manager layer has two different timers with their
own timeout values for TCP connections: connect timeout and read
timeout. Separate the connect and the read TCP timeouts in the
dispatch module too.

Closes #5009

Merge branch '5009-dispatch-separate-connect-and-read-timeouts' into 'main'

See merge request isc-projects/bind9!9698