Use config yaml

• using yaml files to configure instances.
• using cog to generate instance files and thereby verilog.
• use same memory map function return type in apb as axi
• round-robin logic in axi4/axi4lite updated. We now maintain a tiney register per slave to track its priority. This removes the restriction of having only max 5 masters on the crossbars.
• remove README in axi4/test and axi4_lite/test folders
• new targets in Makefile for generating bsv instance files through cogapp
• suppressed warnings during Bluespec compilation
• adding test-config.py to automate generation of legal parameters of various ips.