Rename Primitive Crates (#271)

* Rename Ethereum PoA primitives crate

The "sp" prefix comes from Substrate primitives, since this crate originated
in that repo. However, it is not part of Substrate anymore and its name should
be updated to reflect that.

* Rename currency exchange primitives

* Rust Fmt

* Update import in benchmarking module

* Rust Fmt

* Split pub and no-pub

* Sort toml files.

Co-authored-by: Tomasz Drwięga <[email protected]>