Add support for "int", and int as type when creating Attributes and no metadata is required

[GDYendell]

Often when introspecting devices they will return the type as a string, so it would be convenient to be able to pass this straight into Attributes rather than having to map them to the FastCS types.

Could also consider getting rid of FastCS types and using Annotated[int, min=...]?

Acceptance Criteria

• AttrR("int", ...) is equivalent to AttrR(Int(), ...)
• And other types