Moves `Block` to `frame_system` instead of `construct_runtime` and removes `Header` and `BlockNumber` (#2790)

* Fixes

* Removes unused import

* Uses Block and removes BlockNumber/Header from Chain

* Fixes bridges

* Fixes

* Removes unused import

* Fixes build

* Uses correct RelayBlock

* Minor fix

* Fixes glutton-kusama

* Uses correct RelayBlock

* Minor fix

* Fixes benchmark for pallet-bridge-parachains

* Adds appropriate constraints

* Minor fixes

* Removes unused import

* Fixes integrity tests

* Minor fixes

* Updates trait bounds

* Uses custom bound for AsPrimitive

* Fixes trait bounds

* Revert "Fixes trait bounds"

This reverts commit 0b0f42f583f3a616a88afe45fcd06d31e7d9a06f.

* Revert "Uses custom bound for AsPrimitive"

This reverts commit 838e5281adf8b6e9632a2abb9cd550db4ae24126.

* No AsPrimitive trait bound for now

* Removes bounds on Number

* update lockfile for {"substrate", "polkadot"}

* Formatting

* ".git/.scripts/commands/fmt/fmt.sh"

* Minor fix

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Co-authored-by: parity-processbot <>