Merge pull request #4669 from willmmiles/4597-usermods-not-building

Correct issues with usermods not being linked.
- Explicitly set libArchive: false in usermod library.json files
- Fix up symlink path generation on Windows
- Add validation script to report usermod linkage in resulting binary

usermods/usermod_v2_brightness_follow_sun/library.json

@@ -1,3 +1,4 @@
 {
-  "name": "brightness_follow_sun"
+  "name": "brightness_follow_sun",
+  "build": { "libArchive": false }
 }