Refactor page content generators

CHDataManagement/Generator/Commands/IconCommand.swift

@@ -0,0 +1,24 @@
+
+struct IconCommand: CommandProcessor {
+
+    static let commandType: CommandType = .icons
+
+    let results: PageGenerationResults
+
+    init(content: Content, results: PageGenerationResults, language: ContentLanguage) {
+        self.results = results
+    }
+    
+    func process(_ arguments: [String], markdown: Substring) -> String {
+        var icons = [PageIcon]()
+        for argument in arguments {
+            guard let icon = PageIcon(rawValue: argument) else {
+                invalid(markdown)
+                continue
+            }
+            icons.append(icon)
+        }
+        results.require(icons: icons)
+        return ""
+    }
+}