Updates script parameter documentation

Adds missing descriptions for cleanup, file copying, and download priority parameters to ensure complete help documentation.

Expands the documented supported values for Windows architectures, releases, and SKUs to accurately reflect expanded capabilities for ARM64, Windows Server, and LTSC deployments.

Corrects minor typos, updates default values to match the current implementation, and reorders parameters alphabetically to improve readability.

docs/reference.md

@@ -0,0 +1,19 @@
+---
+title: Reference
+nav_order: 5
+prev_url: /helper_scripts.html
+prev_label: Helper Scripts
+next_url: /parameters_reference.html
+next_label: Parameters Reference
+has_children: true
+has_toc: false
+---
+# Reference
+
+This section contains deep-dive documentation that explains how FFU Builder works behind the UI.
+
+## Available reference guides
+
+- [BuildFFUVM Parameter Reference](/FFU/parameters_reference.html)
+
+{% include page_nav.html %}