Server v4 (#370)

* refactoring-1

introduced pipelines and abstracted download process.go in Downloader interface

* migrated to boltdb from sqlite + session files

* refactoring: config struct & pipelines

* added js runtime for yt-dlp

* updated dockerfile

* added external js runtime, metadata scraping refactor

* updated Dockerfile

* fixed env propagation in docker

* updated package name to v4

* updated readme and cd

README.md

@@ -1,6 +1,10 @@
 > [!CAUTION]
 > Unsupervised AI code is prohibited in this repo.
 
+> [!NOTE]  
+> Read before updating to v4
+> Server v4 migration guide https://github.com/marcopiovanello/yt-dlp-web-ui/wiki/Migrate-to-v4
+
 > [!NOTE]  
 > A poll is up to decide the future of yt-dlp-web-ui frontend! If you're interested you can take part.  
 > https://github.com/marcopiovanello/yt-dlp-web-ui/discussions/223
@@ -16,11 +20,11 @@ Created for the only purpose of *fetching* videos from my server/nas and monitor
 **Docker images are available on [Docker Hub](https://hub.docker.com/r/marcobaobao/yt-dlp-webui) or [ghcr.io](https://github.com/marcopiovanello/yt-dlp-web-ui/pkgs/container/yt-dlp-web-ui)**.
 
 ```sh
-docker pull marcobaobao/yt-dlp-webui
+docker pull marcobaobao/yt-dlp-webui:v4
 ```
 ```sh
-# latest dev
-docker pull ghcr.io/marcopiovanello/yt-dlp-web-ui:latest
+# latest stable
+docker pull ghcr.io/marcopiovanello/yt-dlp-web-ui:v4
 ```
 
 ## Donate to yt-dlp-webui development