* WIP: Get rid of request multiplexer.
* WIP
* Receiver for handling of incoming requests.
* Get rid of useless `Fault` abstraction.
The things the type system let us do are not worth getting abstracted in
its own type. Instead error handling is going to be merely a pattern.
* Make most things compile again.
* Port availability distribution away from request multiplexer.
* Formatting.
* Port dispute distribution over.
* Fixup statement distribution.
* Handle request directly in collator protocol.
+ Only allow fatal errors at top level.
* Use direct request channel for availability recovery.
* Finally get rid of request multiplexer
Fixes#2842 and paves the way for more back pressure possibilities.
* Fix overseer and statement distribution tests.
* Fix collator protocol and network bridge tests.
* Fix tests in availability recovery.
* Fix availability distribution tests.
* Fix dispute distribution tests.
* Add missing dependency
* Typos.
* Review remarks.
* More remarks.
Squirrel