Weight v1.5: Opaque Struct (#12138)

* initial idea

* update frame_support

* update a bunch more

* add ord

* adjust RuntimeDbWeight

* frame_system builds

* re-export

* frame_support tests pass

* frame_executive compile

* frame_executive builds

* frame_system tests passing

* pallet-utility tests pass

* fix a bunch of pallets

* more

* phragmen

* state-trie-migration

* scheduler and referenda

* pallet-election-provider-multi-phase

* aura

* staking

* more

* babe

* balances

* bunch more

* sudo

* transaction-payment

* asset-tx-payment

* last pallets

* fix alliance merge

* fix node template runtime

* fix pallet-contracts cc @athei

* fix node runtime

* fix compile on runtime-benchmarks feature

* comment

* fix frame-support-test

* fix more tests

* weight regex

* frame system works

* fix a bunch

* more

* more

* more

* more

* more

* more fixes

* update templates

* fix contracts benchmarks

* Update lib.rs

* Update lib.rs

* fix ui

* make scalar saturating mul const

* more const functions

* scalar div

* refactor using constant functions

* move impl

* fix overhead template

* use compactas

* Update lib.rs