Move Exceptions in a separate directory + Fixed Range function

Signed-off-by: davidarendsen <davidarendsen@hey.com>

src/Exception/FunctionRequiredSettingMissingException.php

@@ -0,0 +1,14 @@
+<?php
+
+namespace Arendsen\FluxQueryBuilder\Exception;
+
+use Exception;
+
+class FunctionRequiredSettingMissingException extends Exception {
+    
+    public function __construct(string $functionName, string $message)
+    {
+        parent::__construct('Function ' . $functionName . ' - ' . $message);
+    }
+
+}