reorg: move JS ops implementations to cli/js/ops/, part 3 (#4302)

Following JS ops were moved to separate files in cli/js/ops directory:
- net
- tls
- fs

cli/js/ops/fs/read_link.ts

@@ -0,0 +1,20 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+import { sendSync, sendAsync } from "../dispatch_json.ts";
+
+/** Returns the destination of the named symbolic link.
+ *
+ *       const targetPath = Deno.readlinkSync("symlink/path");
+ *
+ * Requires `allow-read` permission. */
+export function readlinkSync(path: string): string {
+  return sendSync("op_read_link", { path });
+}
+
+/** Resolves to the destination of the named symbolic link.
+ *
+ *       const targetPath = await Deno.readlink("symlink/path");
+ *
+ * Requires `allow-read` permission. */
+export async function readlink(path: string): Promise<string> {
+  return await sendAsync("op_read_link", { path });
+}