bitfield dist logging cleanup and enhancements (#5147)

* split metrics from bitfield signing

* cleanup all logging

* add a unit test for subset generation

* chore: add one more test to assert need is properly represented

* u8 as usize

* chore: overseer fixin

* fix test

* Update node/network/bitfield-distribution/src/metrics.rs

Co-authored-by: Andrei Sandu <54316454+sandreim@users.noreply.github.com>

* Update node/network/bitfield-distribution/src/metrics.rs

Co-authored-by: Andrei Sandu <54316454+sandreim@users.noreply.github.com>

* fallout from suggested rename

* consistency

Co-authored-by: Andrei Sandu <54316454+sandreim@users.noreply.github.com>