The `Id`, `Name`, and `Path` value objects are not only message-related
concerns, they're part of the core of the library, hence it makes sense
to place them at the root namespace.
Currently, we’re using scalar values to trace paths. The problem with
that approach is that we can’t create a reliable hierarchy with them, as
we can’t know for sure when a path is the same for different rules. By
using an object, we can easily compare and create a parent-child
relationship with it.
While making these changes, I deemed it necessary to also create objects
to handle Name and Id, which makes the code simpler and more robust. By
having Name and Path, we can create specific stringifiers that allow us
to customise how we render those values.
I didn’t manage to make those changes atomically, which is why this
commit makes so many changes. I found myself moving back and forth, and
making all those changes at once was the best solution I found.
