Make the first user created an admin

To easily bootstrap of administration of the system make the first
regular user account created into an admin account.

server/api/auth/account.post.ts

@@ -29,10 +29,11 @@ export default defineEventHandler(async (event) => {
 			});
 		}
 
+		const firstUser = users.every(user => user.type === "anonymous");
 		user = {
 			id: await nextUserId(),
 			updatedAt: new Date().toISOString(),
-			type: "regular",
+			type: firstUser ? "admin" : "regular",
 			name,
 		};