Implement unique id for module, register, field

As a user I need a means of uniquely referencing modules, registers, fields.

Canonical name?

• module names are globally unique
  • <module name>
• register names are unique within a module
  • <module name>.<register name>
• local field names are unique within a register
  • <module name>.<register name>.<field name>
• global field names are globally unique amongst themselves, but could duplicate module names or register names
  • global.<field name>