Add jq to Docker image and improve UNIT_SOURCE handling

- Include jq in the Docker image for JSON processing.
- Refactor UNIT_SOURCE logic to cleanly update configuration using jq.
- Remove obsolete UNIT_SOURCE handling code.

docker-compose.yml

@@ -1,4 +1,4 @@
-version: '3.7'
+#version: '3.7'
 services:
   app:
     build:
@@ -13,6 +13,8 @@ services:
       - ${DOCKER_APP_PORT}:9000
     volumes:
       - ./app/application:/var/www/html
+    environment:
+      CONTAINER_ROLE: app
 
   queue:
     build: