Add non-default install path option to NESTCodeGeneratorUtils.generate_code_for()

[clinssen]

On the EBRAINS image, NESTML tries to copy the generated .so user extension module into the NEST Simulator install directory, which is not writeable by the user.

Add a feature to install this to another location, or use mkstemp to automatically find a suitable location.

[pnbabu]

We have the option to install the binaries to another location via the install_path argument to the generate_target() function. This is used in this notebook which runs fine with the recent EBRAINS-23.09-rc2 image for EBRAINS.

[clinssen]

Yes, but all tutorial notebooks currently use NESTCodeGeneratorUtils.generate_code_for(). We indeed just have to pass the parameter in the right way—or have generate_code_for() generate a temporary directory (using mkstemp) if the supplied install_path equals None.

[terhorstd]

I've added the install_path to the notebook, so that it passes the tests.