feat(HTTP): Add HTTP discover function

Author: nokome

src/http/discover.ts

@@ -0,0 +1,16 @@
+import { Manifest } from '../base/Executor'
+import { HttpAddress } from '../base/Transports'
+import HttpClient from './HttpClient'
+
+/**
+ * Discover `HttpServer` instances.
+ *
+ * Currently just fetches a `Manifest` from a single `HttpAddress`.
+ */
+export default async function discover(
+  address?: HttpAddress
+): Promise<Manifest[]> {
+  const client = new HttpClient(address)
+  const manifest = await client.manifest()
+  return [manifest]
+}