implement hash size property

src/commonMain/kotlin/com/infendro/hash/HashFunction.kt

@@ -1,6 +1,10 @@
 package com.infendro.hash
 
 sealed class HashFunction {
+    abstract val bytes: Int
+    val bits: Int
+        get() = bytes * 8
+
     abstract fun hash(
         value: ByteArray,
     ): ByteArray