Generate domain information for every port in Manifest files

[martijnbastiaan]

Clocks, resets, and enables currently include their synthesize domain in manifest files:

                {
                    "domain": "System",
                    "width": 1,
                    "name": "clock",
                    "is_clock": true,
                    "type_name": "clock.addBound_types.clk_System"
                },

However, this doesn't happen for "normal" signals:

                {
                    "width": 33,
                    "name": "i",
                    "is_clock": false,
                    "type_name": "i.addBound_types.Maybe"
                }

It's currently not included because HWType does not store domain information for types other than clocks, resets, and enables. I'm not 100% sure, but I'm guessing a proper solution would be to keep all casts, and cast Signal a ~ a where appropriate. There's probably a more hacky way of achieving the same.

Having this information present would help integration with external tooling.