* Add license

* Add rustfmt config

* Add `fmt` CI job

* Add `FILE_HEADER` to files

* Apply `cargo fmt`

* Revert "Apply `cargo fmt`"

This reverts commit 1bfb7a289ff093a9cc1e22318e9c96f5aa9cbfb0.

* Copy `rustfmt.toml` from Substrate over

* Apply `cargo fmt`

* Add license check

* Fix stage name

* Use nightly for `rustfmt`