carsim: Remove staticx and switch PyInstaller to directory more

[mikehaller]

Using staticx and PyInstaller "file" mode creates a fat-binary which needs to be uncompressed at runtime.

For containerized applications which are supposed to run in read-only mode, this is bad behaviour and unnecessary:

• staticx unpacks to /tmp, which is not a real tmpfs. Hence, the container runtime creates a persistent volume/overlay
• on shutdown of the container, staticx runs a clean up script to delete the tmp files. however, in automotive embedded systems, sress testing includes hard powering-off the devices, which leads to garbage piling up (leftover overlay volumes).
• a good citizen app would be run in read-only mode, so that no persistent volumes are created at runtime. that requires /tmp to be mounted to a real tmpfs - or even better, the application does not create temp files at all.
• for an application like carsim, which has no persistence requirements, as the states are kept in the Kuksa Databroker, the container should run in read-only mode.

Tasks:

• Remove staticx from the build in the Dockerfile
• Change PyInstaller to directory mode
• Test the container and functionality with docker run ... --read-only ...