* Copy-Pasta Call code from mock Rococo to mock Westend runtime

* Update Westend client to include signing and call related code

* Add missing part of license header

* Move `account_info_storage_key` to `polkadot-core` crate

* Update copyright date to 2021

* Bump date in license header template

* Remove chains.

* Move relay clients.

* Flatten generic.

* Fix fmt.