Added toString() implementation

fints4k/src/commonMain/kotlin/net/codinux/banking/fints/log/MessageContext.kt

@@ -14,4 +14,6 @@ class MessageContext(
     val messageNumber: Int,
     val bank: BankData,
     val account: AccountData?
-)
+) {
+    override fun toString() = "${jobNumber}_${dialogNumber}_$messageNumber ${bank.bankCode} $jobType $messageType"
+}

fints4k/src/commonMain/kotlin/net/codinux/banking/fints/model/MessageLogEntry.kt

@@ -25,7 +25,7 @@ open class MessageLogEntry(
         get() = messageTrace + "\n" + message
 
     override fun toString(): String {
-        return "$type $message"
+        return "$context $type $message"
     }
 
 }