Wrappers of custom bitwidths

[definelicht]

Christian Lutzweiler has suggested making wrapper types and utility functions supporting custom bitwidths. Features could include:

• Portable custom bitwidth type (Xilinx uses ap_uint, OpenCL doesn't support it, i++ might have something).
• Utility functions for determining bitwidths (e.g., using hlslib::ConstLog2).
• Conversion functions between different bitwidths, potentially emitting compile-time errors if not explicitly overwritten for unsafe conversions.