Move Pre-emptive requests and reauthentication jobs out of Chewie

[MichaelWasher]

There a too many of timer-based async actions running inside the Chewie main file making it difficult to read.

[ ] Move port reauthentication and session management out of Chewie.
[ ] Move pre-emptive identity request generation and management out of Chewie (probably into a port SM or EAP SM)