This commit switches `model::Type::ID` from being a GUID to be a
progressive number, in order to make things easier for humans.
On top of this, this commit introduces the following changes:
* TypeCopier: import all the necessary PrimitiveTypes and improve
handling of CustomName.
* Move Kind as the last field of the key of each TupleTree type used in
an `UpcastablePointer`.
* Update the ground truth of tests to ignore the `CustomName` in favor
of focusing on `OriginalName`.
* Increase adoption of `model::Binary::makeType`, equivalent to
`Binary.recordNewType(makeType<model::*Type>())`.
This commit introduces a change in `revng model compare` so that, for
dictionary entries whose keys start with `$`, it is ensured that the
length of the associated value (be it a list or a dictionary) is the
same.
Alessandro Di Federico