feat(Experience): add data type helper methods

add data type helper methods:
- ByteArray to HexString (String)
- String to Binary (ByteArray)

Hashing/src/commonMain/kotlin/io/iohk/prism/hashing/internal/ByteArrayExtension.kt

@@ -0,0 +1,5 @@
+package io.iohk.prism.hashing.internal
+
+fun ByteArray.toHexString(): String {
+    return joinToString("") { (0xFF and it.toInt()).toString(16).padStart(2, '0') }
+}

Hashing/src/commonMain/kotlin/io/iohk/prism/hashing/internal/StringExt.kt

@@ -0,0 +1,11 @@
+package io.iohk.prism.hashing.internal
+
+fun String.toBinary(): ByteArray {
+    val blen = this.length / 2
+    val buf = ByteArray(blen)
+    for (i in 0 until blen) {
+        val bs = this.substring(i * 2, i * 2 + 2)
+        buf[i] = bs.toInt(16).toByte()
+    }
+    return buf
+}