api and storage restructure

lib/api/requestCache.dart

@@ -79,3 +79,38 @@ abstract class RequestCache<T extends ApiResponse?> {
   Future<T> onLoad();
 
 }
+
+/// Concrete [RequestCache] that delegates the two overrides to functions
+/// passed in the constructor. Used to collapse the dozens of one-class-per-
+/// endpoint cache files that all just forward to `<Endpoint>().run()` and
+/// `<Response>.fromJson(jsonDecode(...))`.
+class SimpleCache<T extends ApiResponse?> extends RequestCache<T> {
+  final Future<T> Function() _loader;
+  final T Function(Map<String, dynamic> json) _fromJson;
+
+  SimpleCache({
+    required int cacheTime,
+    required Future<T> Function() loader,
+    required T Function(Map<String, dynamic> json) fromJson,
+    void Function(T)? onUpdate,
+    void Function(T)? onCacheData,
+    void Function(T)? onNetworkData,
+    void Function(Exception)? onError,
+    bool? renew,
+  })  : _loader = loader,
+        _fromJson = fromJson,
+        super(
+          cacheTime,
+          onUpdate,
+          onError: onError ?? RequestCache.ignore,
+          renew: renew,
+          onCacheData: onCacheData,
+          onNetworkData: onNetworkData,
+        );
+
+  @override
+  Future<T> onLoad() => _loader();
+
+  @override
+  T onLocalData(String json) => _fromJson(jsonDecode(json));
+}