Test the gcc compiler for CVA6 and llvm-generic for snitch core in SNAX Container

[IveanEx]

We are going to abandon the original Occamy docker image and use SNAX image for both hardware and software generation. The toolchain is already available in KULeuven-MICAS/snax_cluster#234 and we need to do several modifications to use it:

• Bootrom: modify the Makefile in target/rtl/bootrom and target/fpga/bootrom and validate the correct compilation by downloading the Bootrom on FPGA
• Device Software: normally nothing needs to be modified. Just to validate if the software is linked at the correct memory offset
• Host Software: modify the toolchain and test the compilation. Make sure that the correct loader script is emitted during the first compilation; and the final linking is conducted correctly.

[IveanEx]

Please wait KULeuven-MICAS/snax_cluster#278 to be merged into main before starting the actual work.