Occamy: Generate different RTL for RTL/FPGA

[zarubaf]

We probably need to think about generating a couple of different systems in occamygen.py.
I can at least think about two in that context:

1. RTL Sim
2. FPGA
3. (ASIC in the private wrapper repo)

I think we have all the necessary ingredients for this. What is missing is:

• Create a second(/third) configuration file. Using jsonref we could also share the cluster configuration between the system configuration.
• Generate the RTL into dedicated directories
• (Manually) adapt the Bender.yml to include the appropriate files.