Upstream Statemine v4 Changes (#649)

* bump runtime spec version

* remove applied runtime migrations

* bump transaction_version

necessary because of extrinsic API changes to pallet-xcm
https://github.com/paritytech/polkadot/pull/3693

* Fix Benchmarks for Statemine-V4 release (#639)

* register validators

* register_as_candidate & leave_intent fixed

* new_session benchmark fixed

* intent_leave_modified

* clean up

* clean up

* benchmark script updated

* update cargo.lock

* done

Co-authored-by: Alexander Popiak <alexander.popiak@parity.io>

* Version bump (#648)

* Version bump

fix #646

* Revert "Version bump"

This reverts commit 07517e0e76a37a1dd67176fec0524d0211666635.

* Bump polkadot-collator version

* Update polkadot-parachains/Cargo.toml

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

* Update deps

* Bump version to 4.0.0

Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>

* cargo toml fix

* update deps and remove DisabledValidatorThreshold

* cargo +nightly fmt

* fix compile error

* fix client tests after Polkadot update

Co-authored-by: Ignacio Palacios <ignacio.palacios.santos@gmail.com>
Co-authored-by: Chevdor <chevdor@users.noreply.github.com>
Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>