Add ss58 address for Dark network (#6982)

Hello,
This PR adds a new ss58 address 17 for Dark network.
Thanks!

Author: DarkPay

primitives/core/src/crypto.rs

@@ -472,6 +472,8 @@ ss58_address_format!(
 		(13, "substratee", "Any SubstraTEE off-chain network private account (*25519).")
 	KulupuAccount =>
 		(16, "kulupu", "Kulupu mainnet, standard account (*25519).")
+	DarkAccount =>
+		(17, "dark", "Dark mainnet, standard account (*25519).")
 	DarwiniaAccount =>
 		(18, "darwinia", "Darwinia Chain mainnet, standard account (*25519).")
 	StafiAccount =>