abi: Solidify arch-agnostic APIs.

[lkorenc]

Prerequisites

• I have read the documentation and the proposed feature is not implemented.

Description

Classification algorithm is currently designed in a way that splits between data (and apis) presented back to the user and internal classification. However, only x86_64 is really supported. Add stub of Aarch64 classification and by doing that solidify the user facing apis.

• Add api to choose architecture
• Make sure we are not leaking any internal abstraction (even by accident - hide with class access)
• Adapt emit/lower conversion passes to account for multiple architectures and if needed provide hook points.