Add Vision Support (#889)

# Summary of Changes
* New UI to show preview of image uploads
* ChatML message changes to support gpt-4o vision based responses on images
* AWS S3 image uploads for persistent image context in conversations
* Database changes to have `vision_enabled` option in server admin panel while configuring models
* Render previously uploaded images in the chat history, show uploaded images for pending msgs
* Pass the uploaded_image_url through to subqueries
* Allow image to render upon first message from the homepage
* Add rendering support for images to shared chat as well
* Fix some UI/functionality bugs in the share page
* Convert user attached images for chat to webp format before upload
* Use placeholder to attached image for data source, response mode actors
* Update all clients to call /api/chat as a POST instead of GET request
* Fix copying chat messages with images to clipboard

TLDR; Add vision support for openai models on Khoj via the web UI!

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Co-authored-by: sabaimran <narmiabas@gmail.com>
Co-authored-by: Debanjum Singh Solanky <debanjum@gmail.com>

src/interface/web/app/factchecker/page.tsx

@@ -79,7 +79,7 @@ async function verifyStatement(
     let verificationMessage = `${verificationPrecursor} ${message}`;
     const apiURL = `${chatURL}?q=${encodeURIComponent(verificationMessage)}&client=web&stream=true&conversation_id=${conversationId}`;
     try {
-        const response = await fetch(apiURL);
+        const response = await fetch(apiURL, { method: "POST" });
         if (!response.body) throw new Error("No response body found");
 
         const reader = response.body?.getReader();