Add sveltekit-rate-limiter & Fix Rate Limiter Issue

[davidgxue]

Description

• See Ask Astro Sanic Rate Limiter Incorrectly Blocks Requests by Treating All Requests as a Single IP Source #268 for details of why the error occurs. This won't be explained again in this PR.
• TL;DR: svelte backend (cloudflare) is sitting in front of the GCP API therefore it is not possible to do IP based rate limiting in sanic. Instead, we must implement it in svelte for now.
• In production environment, I have set cookie rate limit to be 5 requests per minute, and IP based rate limit to be 100 per day using cloudflare's environment varables

Technical Changes

• Add sveltekit-rate-limiter
• Revert the old PR that caused the rate limit issue (where all requests are misinterpreted as the same IP)

Tests

Setup:

• In Cloudflare, I have set the dev environment to temporarily have these environment varaibles
  

1. Test cookie rate limiter. This should trigger after 5 requests using the same browser

Screen.Recording.2024-01-24.at.2.32.14.PM.mov

2. Using incognito, we can continue to send requests without being blocked. But after 5 more requests we hit our IP based rate limit

3. Now, just to be safe, I used a different computer with VPN and reconnected to the same dev website. And confirmed that I can continue to send additional requests

closes #268

[cloudflare-pages]

Deploying with    Cloudflare Pages

Latest commit:	cb04c91
Status:	✅  Deploy successful!
Preview URL:	https://af57f4ba.ask-astro.pages.dev
Branch Preview URL:	https://fix-rate-limiter-issue.ask-astro.pages.dev

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[pankajkoti]

Nice. Just have one question inline regarding the env vars.

[sunank200]

LGTM.