Update generation

- Move to global objects for files and validation
- Only write changed files
- Check images for changes before scaling
- Simplify code

WebsiteGenerator/Templates/Elements/ThumbnailTemplate.swift

@@ -2,7 +2,7 @@ import Foundation
 
 protocol ThumbnailTemplate {
 
-    func generate(_ content: [ThumbnailKey : String], shouldIndent: Bool) throws -> String
+    func generate(_ content: [ThumbnailKey : String], shouldIndent: Bool) -> String
 }
 
 enum ThumbnailKey: String, CaseIterable {