Corrected AVR8 TDF EESAVE fuse bit validation, and a little refactoring

build/scripts/TargetDescriptionFiles/AVR8/FuseBitsDescriptor.php

@@ -0,0 +1,16 @@
+<?php
+namespace Bloom\BuildScripts\TargetDescriptionFiles\Avr8;
+
+class FuseBitsDescriptor
+{
+    const FUSE_TYPE_LOW = 'low';
+    const FUSE_TYPE_HIGH = 'high';
+    const FUSE_TYPE_EXTENDED = 'extended';
+
+    public ?string $fuseType = null;
+
+    public function __construct(?string $fuseType)
+    {
+        $this->fuseType = $fuseType;
+    }
+}