feat: Integrate setup behaviour

This adds options for enabling setup to the config folder.
All default configs with permanent storage (file/sparql)
are configured to require setup at server start.
Memory-based configs merely have it as an option.

src/index.ts

@@ -317,6 +317,7 @@ export * from './util/handlers/BooleanHandler';
 export * from './util/handlers/ConditionalHandler';
 export * from './util/handlers/ParallelHandler';
 export * from './util/handlers/SequenceHandler';
+export * from './util/handlers/StaticHandler';
 export * from './util/handlers/UnsupportedAsyncHandler';
 export * from './util/handlers/WaterfallHandler';
 

src/util/handlers/StaticHandler.ts

@@ -0,0 +1,22 @@
+import { AsyncHandler } from './AsyncHandler';
+
+/**
+ * A handler that always resolves and always returns the stored value.
+ * Will return undefined if no value is stored.
+ *
+ * The generic type extends `any` due to Components.js requirements.
+ */
+// eslint-disable-next-line @typescript-eslint/no-unnecessary-type-constraint
+export class StaticHandler<T extends any = void> extends AsyncHandler<any, T> {
+  private readonly value?: T;
+
+  public constructor(value?: T) {
+    super();
+    this.value = value;
+  }
+
+  public async handle(): Promise<T> {
+    // eslint-disable-next-line @typescript-eslint/no-unnecessary-type-assertion
+    return this.value!;
+  }
+}