Reduce Dockerfile layers and optimize build

[YoussefBayouli]

Combined multiple apk add steps in both stages to reduce the number of layers.

Removed the apk del --purge deps since curl and vim are still required, so no need to remove them.

Removed redundant apk --update since --no-cache already ensures that the latest package versions are installed without caching.

[derailed]

@YoussefBayouli Thank you for this update! Unless I am missing it, the resulting image size is now ~135mb vs ~99.8mb ;(