SVGPCB integration improvements

[ducky64]

From building several layout templates, improvements could be made to make the whole process easier:

• Consistent naming API, that matches the pathname of the HDL component. Two parts:
  • Hierarchical naming - the returned object should be a scope and automatically handle adding the container's pathname prefix as needed - the function code should not deal with this.
  • Character remapping - e.g., replace , with _, must match the behavior in the netlist compilers.
• Generate consistent KiCad tstamps, to allow proper netlist updates in KiCad layout. Either tstamp generation could be part of a compiler pass and be part of the IR (unclear how this would work with the current structure - maybe passes can introduce new parameters?) or add a tstamp generation helper to SVGPCB.
  • Probably not possible to generate tstamps as part of the SVGPCB layout template generation pass, since it would need to name each individual element.
• Some graphical library to avoid needing to add primitives like vector-add in each layout template