SIM_LOG_DIR points to /etc/astra-sim

[marcodamico]

By pointing to /etc/astra-sim, we must use sudo permission to run the ./build script or:

mkdir: cannot create directory ‘/etc/astra-sim’: Permission denied
mkdir: cannot create directory ‘/etc/astra-sim’: Permission denied
mkdir: cannot create directory ‘/etc/astra-sim’: Permission denied
mkdir: cannot create directory ‘/etc/astra-sim’: Permission denied
mkdir: cannot create directory ‘/etc/astra-sim’: Permission denied
mkdir: cannot create directory ‘/etc/astra-sim’: Permission denied

I propose using "${SCRIPT_DIR:?}"/log as the log folder.

[tianhao909]

agree ～