Add support for running ilab container in background or foreground mode

[eranco74]

• Introduce PODMAN_BACKGROUND_MODE environment variable to control podman run mode
• Use --detach flag for background mode and --interactive flag for foreground mode
• Update PODMAN_COMMAND to include the appropriate flag based on PODMAN_BACKGROUND_MODE

This change allows the script to conditionally run ilab podman containers in the background or foreground based on the value of the PODMAN_BACKGROUND_MODE environment variable