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 <tomasz@parity.io>

bridges/modules/ethereum/src/validators.rs

@@ -16,7 +16,7 @@
 
 use crate::error::Error;
 use crate::{ChangeToEnact, Storage};
-use primitives::{Address, Header, HeaderId, LogEntry, Receipt, U256};
+use bp_eth_poa::{Address, Header, HeaderId, LogEntry, Receipt, U256};
 use sp_std::prelude::*;
 
 /// The hash of InitiateChange event of the validators set contract.
@@ -278,8 +278,8 @@ pub(crate) mod tests {
 	use crate::mock::{run_test, validators_addresses, validators_change_receipt, TestRuntime};
 	use crate::DefaultInstance;
 	use crate::{BridgeStorage, Headers, ScheduledChange, ScheduledChanges, StoredHeader};
+	use bp_eth_poa::compute_merkle_root;
 	use frame_support::StorageMap;
-	use primitives::compute_merkle_root;
 
 	const TOTAL_VALIDATORS: usize = 3;