chore(build): Avoid prebuilding api side, instead use an esbuild plugin

[dac09]

What does this PR do?

Removes FS-based prebuild process
This changes the API side build process to "prebuild" files in memory with babel, rather than write to the .redwood/prebuild folder. Instead of prebuilding to file system, then transforming with esbuild again, we now use an esbuild plugin to do the same in memory - eliminating all the unnecessary read and writes to the FS.

We should see the dev server (and build process) speed up, particularly for Windows users

---

Notes
a. In order to use plugins, I switched to the async esbuild build function. This is likely better for perf anyway!
b. We still prebuild files for our tests. This is still handy to do!
c. Renamed prebuildFile -> transformWithBabel to remove any confusion!
d. I've verified that you can debug the api side by setting breakpoints

[replay-io]

16 replays were recorded for c441253.

0 Failed

16 Passed

requireAuth graphql checks

    ```
    locator.waitFor: Target closed
    =========================== logs ===========================
    waiting for locator('.rw-form-error-title').locator('text=You don\'t have permission to do that') to be visible
    ============================================================
    ```
  </ol>
</details>
<li><a href=https://app.replay.io/recording/0693a394-8248-4f1d-990b-a0e782817cb6>useAuth hook, auth redirects checks</a></li>
<li><a href=https://app.replay.io/recording/ddebf561-81a4-487f-9ff3-3f0f0a0f6d10>Check that a specific blog post is prerendered</a></li>
<li><a href=https://app.replay.io/recording/aa152027-b947-40f2-bcd2-1110820c4911>Check that about is prerendered</a></li>
<li><a href=https://app.replay.io/recording/c46342f3-e9a7-405a-b11b-5bcd559784dc>Check that homepage is prerendered</a></li>
<li><a href=https://app.replay.io/recording/41008c3a-2463-4573-93b0-53bdb80e6333>Check that meta-tags are rendering the correct dynamic data</a></li>
<li><a href=https://app.replay.io/recording/e6a43862-f27a-4977-9fd3-462bd853b4d4>Check that you can navigate from home page to specific blog post</a></li>
<li><a href=https://app.replay.io/recording/97f16d8c-4d82-48f9-9757-13eb0e479400>Waterfall prerendering (nested cells)</a></li>
<li><a href=https://app.replay.io/recording/9dc14ec0-5c14-4329-8843-cac7da0ab3bc>RBAC: Admin user should be able to delete contacts</a></li>
<li><a href=https://app.replay.io/recording/77879ce4-feaf-44c7-8f6c-06ad94fccab8>RBAC: Should not be able to delete contact as non-admin user</a></li>
<li><a href=https://app.replay.io/recording/e0ded03d-05ac-416e-804e-97a815c6d077>Smoke test with dev server</a></li>
<li><a href=https://app.replay.io/recording/467188b6-cafa-4bd7-b652-2a6348a39056>Smoke test with rw serve</a></li>
<li><a href=https://app.replay.io/recording/254581da-efd0-4650-b6d6-fbd1a3d0861d>Loads Cell mocks when Cell is nested in another story</a></li>
<li><a href=https://app.replay.io/recording/17cb2ed7-1298-4ed1-8d32-132628a01f79>Loads Cell Stories</a></li>
<li><a href=https://app.replay.io/recording/3ca15030-0185-45d4-87b3-92740db673df>Loads MDX Stories</a></li>
<li><a href=https://app.replay.io/recording/252a0b91-de03-41eb-a0e3-e8f876a2a436>Mocks current user, and updates UI while dev server is running</a></li>

View test run on Replay ↗︎

[jtoar]

Looking good @dac09! I was trying to come up with a few more ideas around error reporting when transforming with Babel doesn't work for whatever reason, but don't have any concrete suggestions yet. But submitting this review now to get post the two comments I had

[dac09]

Todo

• Look into whether builds are ok on Windows
• Refactor nftPack tests to avoid actually building the API side