Refactor demo login as an authentication method

Use the authentication method system for the demo login and the
generated accounts.  This makes it possible to toggle it off on
production systems as these shouldn't have it enabled at all.

stores/session.ts

@@ -44,14 +44,6 @@ export const useSessionStore = defineStore("session", () => {
 			state.id.value = session?.id;
 			state.push.value = session?.push ?? false;
 		},
-		async logIn(name: string) {
-			const res = await $fetch.raw("/api/auth/login", {
-				method: "POST",
-				body: { name },
-			});
-			await actions.fetch();
-			return `/api/auth/login replied: ${res.status} ${res.statusText}`;
-		},
 		async logOut() {
 			try {
 				await $fetch.raw("/api/auth/session", {