refact: Rename app-init container to init container

Author: simonwalz

docs/development-guide.md

@@ -21,7 +21,7 @@ CuOS consistens of multiple services and containers.
 |---|---|
 | `cuos-init` | Initialize the system. Setup hostname, network, file system,  |
 | `cuos-api` | API for interaction with the system |
-| `cuos-app-init` | Ensure to start App Init Container container |
+| `cuos-app-init` | Ensure to start Init Container container |
 | `cuos-updater` | Helper container to replace/rollback the system, kernel, initrd and boot config. Started by `cuos-api` or your application. |
 
 ## Development Variants

system/cuos/app-init.sh

@@ -88,7 +88,7 @@ download_image() {
 }
 
 CONTAINER_NAME="cuos-app"
-if ! INITIAL_IMAGE="$(image_url "initial")"; then
+if ! INITIAL_IMAGE="$(image_url "init" || image_url "initial")"; then
   report_err "cuos:application:image_not_defined" "Application image not defined"
   action_on_failure
 fi