Move salmonKey to Salmon class

move the salmonKey function from Crypto to Salmon

src/Util/Crypto.php

@@ -215,16 +215,6 @@ class Crypto
 		return $key;
 	}
 
-	/**
-	 * @param string $pubkey public key
-	 * @return string
-	 */
-	public static function salmonKey($pubkey)
-	{
-		self::pemToMe($pubkey, $m, $e);
-		return 'RSA' . '.' . base64url_encode($m, true) . '.' . base64url_encode($e, true);
-	}
-
 	/**
 	 * @param integer $bits number of bits
 	 * @return mixed