Refactors services with defaultConfig and polled data.

Much more simpler code base. Each service requires a poll functioon to poll its
status. If type is defined, and the registered '+service.ts' exports a poll
ServicePoller, it will be used. Otherwise, a generic poll mechanism is used.

src/lib/services/pihole/+service.ts

@@ -1,28 +1,29 @@
 import type { ServiceConfig } from '$lib/config';
-import { type ServiceData, type ServiceHandler } from '../service';
+import type { ServicePoller } from '../service';
 
-export const handle: ServiceHandler = async (config: ServiceConfig) => {
-	const res: ServiceData = {
-		logo: 'https://cdn.rawgit.com/pi-hole/graphics/master/Vortex/Vortex.svg',
-		subtitle: 'Sends ads into a black hole'
-	};
+export const config: Partial<ServiceConfig> = {
+	title: 'Pi-hole',
+	logo: 'https://cdn.rawgit.com/pi-hole/graphics/master/Vortex/Vortex.svg',
+	subtitle: 'Sends ads into a black hole'
+};
 
+export const poll: ServicePoller = async (config: ServiceConfig) => {
 	try {
 		const resp: Response = await fetch(
 			config.url + '/api.php?summaryRaw&auth=' + config.api_token
 		);
-		res.status = resp.ok ? 'online' : 'offline';
 		const raw = await resp.json();
-		res.data = {
-			queries_today: raw.dns_queries_today,
-			ads_percentage: raw.ads_percentage_today,
-			status: raw.status,
-			client: raw.unique_clients
+		return {
+			status: resp.ok ? 'online' : 'offline',
+			data: {
+				queries_today: raw.dns_queries_today,
+				ads_percentage: raw.ads_percentage_today,
+				status: raw.status,
+				client: raw.unique_clients
+			}
 		};
 	} catch (error) {
-		res.status = 'offline';
 		console.warn('could not fetch pihole status: ' + error);
+		return { status: 'offline' };
 	}
-
-	return res;
 };