Strongly type invokeHook

Add strong typing of the invokeHook function to prevent incorrect
paramaters being passed to plugin hooks. This detected a few places
where the parameters passed were incorrect.

packages/controller/src/Controller.ts

@@ -661,7 +661,7 @@ export default class Controller {
 
 		let instance = new InstanceInfo({ config: instanceConfig, status: "unassigned" });
 		this.instances!.set(instanceId, instance);
-		await lib.invokeHook(this.plugins, "onInstanceStatusChanged", instance, null);
+		await lib.invokeHook(this.plugins, "onInstanceStatusChanged", instance);
 		this.addInstanceHooks(instance);
 		return instance;
 	}

packages/controller/src/HostConnection.ts

@@ -233,7 +233,7 @@ export default class HostConnection extends BaseConnection {
 					instanceConfig.get("instance.id"), instanceConfig.serialize("host")
 				)
 			);
-			await lib.invokeHook(this._controller.plugins, "onInstanceStatusChanged", newInstance, null);
+			await lib.invokeHook(this._controller.plugins, "onInstanceStatusChanged", newInstance);
 		}
 
 		// Push lists to make sure they are in sync.

packages/controller/src/routes.ts

@@ -37,8 +37,7 @@ async function getMetrics(req: Request, res: Response, next: any) {
 	const controller: Controller = req.app.locals.controller;
 
 	let results: lib.CollectorResult[] = [];
-	type ResultIterator = AsyncIterable<lib.CollectorResult> | Iterable<lib.CollectorResult>
-	let pluginResults = await lib.invokeHook(controller.plugins, "onMetrics") as ResultIterator[];
+	let pluginResults = await lib.invokeHook(controller.plugins, "onMetrics");
 	for (let metricIterator of pluginResults) {
 		for await (let metric of metricIterator) {
 			results.push(metric);