Remove BoundedVec half-impls in xcm (#6636)

* Replace sp-core dependency with more primitive crates

* Remove BoundedVec half-impls in xcm

* Fixes

* Bump bounded-collections

* Address review comments

* Bump bounded-collections

* Fix benchmarks

* Fixes

* Fixes

* cargo fmt

* Fix tests

* Update url

* Bump url to 2.3.1

* Bump anyhow

* Use bounded-collections in pallet-xcm

* Update substrate