Split Operational and Normal weight (#5954)

* Split operational and normal weight

* Update other parts of the code

* relatively minor changes to add/fix behavior

* Limit reported block weight for fee adjustment

* fix test

* explicit match

* Move common logic out

* Update frame/system/src/lib.rs

Co-authored-by: Gavin Wood <gavin@parity.io>

* API improvement @bkchr



Co-authored-by: Gavin Wood <gavin@parity.io>