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/DeleteChat.tsx

@@ -3,6 +3,7 @@ import { Dialog, Transition } from '@headlessui/react';
 import { Fragment, useState } from 'react';
 import { toast } from 'sonner';
 import { Chat } from '@/app/library/page';
+import { getServerEnv } from '@/lib/serverEnvironment';
 
 const DeleteChat = ({
   chatId,
@@ -20,7 +21,7 @@ const DeleteChat = ({
     setLoading(true);
     try {
       const res = await fetch(
-        `${process.env.NEXT_PUBLIC_API_URL}/chats/${chatId}`,
+        `${await getServerEnv("BACKEND_API_URL")}/chats/${chatId}`,
         {
           method: 'DELETE',
           headers: {