🐳 : Further Docker build Cleanup & Docs Update (#1502)

* refactor: post-cleanup changes:
- add more unnecessary paths to .dockerignore
- remove librechat.yaml from main compose file (prevents from being required)
- do not create librechat.yaml during build (does nothing)

* docs: make config file instructions easier to read, more info throughout other docs

* docs: add custom config to menu

* Update custom_config.md

* Update docker_compose_install.md

docs/install/configuration/docker_override.md

@@ -34,7 +34,18 @@ Open your `docker-compose.override.yml` file with vscode or any text editor.
 
 Make your desired changes by uncommenting the relevant sections and customizing them as needed.
 
-For example, if you want to use a prebuilt image for the `api` service and expose MongoDB's port, your `docker-compose.override.yml` might look like this:
+For example, if you want to make sure Docker can use your `librechat.yaml` file for [custom configuration](./custom_config.md), it would look like this:
+
+```yaml
+version: '3.4'
+
+services:
+  api:
+    volumes:
+      - ./librechat.yaml:/app/librechat.yaml
+```
+
+Or, if you want to use a prebuilt image for the `api` service and expose MongoDB's port, your `docker-compose.override.yml` might look like this:
 
 ```yaml
 version: '3.4'