Added automatic docker build on merge to master

This PR includes:
- Automatic build & push to docker hub when pushing to master, or when triggering a workflow dispatch on master
- Automatic docker build on pull requests to validate changes
- Updated the docker-compose.yaml to use the container images, rather than building locally
- Added support for defining backend settings using the container environment 
  -> All options defined in config.toml can now be loaded instead from the environment
  -> Order of precedence is environment definition, config.toml, and finally default inline configuration defined in config.ts
- Added support for defining frontend settings using the container environment
  -> Added a dynamic api route to load the container environment definitions on the server, and provide them to the client
  -> Added a library function to fetch from the newly created API, caching the response in the session storage
  -> Modified existing calls to `process.env` to use the new library function
  -> Left the initial statically compiled environment definitions in place as a backup definition, if no environment definitions are provided

Remaining tasks todo before able to merge to [ItzCrazyKns/Perplexica](https://github.com/ItzCrazyKns/Perplexica):
- Add secret definitions for `DOCKER_USERNAME` and `DOCKER_PASSWORD` to [ItzCrazyKns/Perplexica](https://github.com/ItzCrazyKns/Perplexica) to ensure push to dockerhub works on base branch
- Update documentation with information about changes

ui/components/ChatWindow.tsx

@@ -10,6 +10,7 @@ import { toast } from 'sonner';
 import { useSearchParams } from 'next/navigation';
 import { getSuggestions } from '@/lib/actions';
 import Error from 'next/error';
+import { getServerEnv } from '@/lib/serverEnvironment';
 
 export type Message = {
   messageId: string;
@@ -22,13 +23,16 @@ export type Message = {
 };
 
 const useSocket = (
-  url: string,
+  url: string | null,
   setIsWSReady: (ready: boolean) => void,
   setError: (error: boolean) => void,
 ) => {
   const [ws, setWs] = useState<WebSocket | null>(null);
 
   useEffect(() => {
+    if (!url) {
+      return;
+    }
     if (!ws) {
       const connectWs = async () => {
         let chatModel = localStorage.getItem('chatModel');
@@ -39,7 +43,7 @@ const useSocket = (
         );
 
         const providers = await fetch(
-          `${process.env.NEXT_PUBLIC_API_URL}/models`,
+          `${await getServerEnv("BACKEND_API_URL")}/models`,
           {
             headers: {
               'Content-Type': 'application/json',
@@ -220,7 +224,7 @@ const loadMessages = async (
   setNotFound: (notFound: boolean) => void,
 ) => {
   const res = await fetch(
-    `${process.env.NEXT_PUBLIC_API_URL}/chats/${chatId}`,
+    `${await getServerEnv("BACKEND_API_URL")}/chats/${chatId}`,
     {
       method: 'GET',
       headers: {
@@ -260,6 +264,8 @@ const loadMessages = async (
 };
 
 const ChatWindow = ({ id }: { id?: string }) => {
+  const [wsServerUrl, setWsServerUrl] = useState<string | null>(null);
+
   const searchParams = useSearchParams();
   const initialMessage = searchParams.get('q');
 
@@ -271,7 +277,7 @@ const ChatWindow = ({ id }: { id?: string }) => {
 
   const [isWSReady, setIsWSReady] = useState(false);
   const ws = useSocket(
-    process.env.NEXT_PUBLIC_WS_URL!,
+    wsServerUrl,
     setIsWSReady,
     setHasError,
   );
@@ -323,6 +329,15 @@ const ChatWindow = ({ id }: { id?: string }) => {
     }
   }, [isMessagesLoaded, isWSReady]);
 
+  useEffect(() => {
+    const fetchWsServerUrl = async () => {
+      const url = await getServerEnv("BACKEND_WS_URL");
+      setWsServerUrl(url);
+    };
+
+    fetchWsServerUrl();
+  }, []);
+
   const sendMessage = async (message: string) => {
     if (loading) return;
     setLoading(true);