feat: export images, machines, and volumes from API module

src/api/mod.ts

···
 import { bearerAuth } from "hono/bearer-auth";
 import { parseFlags } from "@cliffy/flags";
 
+export { images, machines, volumes };
+
 export default function () {
   const token = Deno.env.get("FREEBSD_UP_API_TOKEN") ||
     crypto.randomUUID();

src/mod.ts

···
 export * from "./types.ts";
 export * from "./utils.ts";
 export * from "./volumes.ts";
+export * from "./api/mod.ts";