feat(chatgpt-browser): add support for multiple GPT models

This commit adds support for multiple GPT models in the chatGPT-browser
client. The available models are now stored in a Map object, which maps
the model label to its corresponding model.

The commit adds a new component, ChatGPTOptions, to the client
UI to allow the user to select the GPT model to use in the chat. The
component is only displayed when the chatGPT-browser endpoint is
selected.

client/src/utils/handleSubmit.js

@@ -50,7 +50,7 @@ const useMessageHandler = () => {
     } else if (endpoint === 'chatGPTBrowser') {
       endpointOption = {
         endpoint,
-        model: currentConversation?.model || 'text-davinci-002-render-sha'
+        model: currentConversation?.model || 'Default (GPT-3.5)'
       };
       responseSender = 'ChatGPT';
     } else if (endpoint === null) {