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!

---------

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

src/interface/web/app/components/chatHistory/chatHistory.tsx

@@ -267,6 +267,7 @@ export default function ChatHistory(props: ChatHistoryProps) {
                                             created: message.timestamp,
                                             by: "you",
                                             automationId: "",
+                                            uploadedImageData: message.uploadedImageData,
                                         }}
                                         customClassName="fullHistory"
                                         borderLeftColor={`${data?.agent.color}-500`}
@@ -309,6 +310,7 @@ export default function ChatHistory(props: ChatHistoryProps) {
                                 created: new Date().getTime().toString(),
                                 by: "you",
                                 automationId: "",
+                                uploadedImageData: props.pendingMessage,
                             }}
                             customClassName="fullHistory"
                             borderLeftColor={`${data?.agent.color}-500`}