abi: Add abstraction over bit and byte sizes.

[lkorenc]

Prerequisites

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

Description

In the ABI component we often need to do computations that involve reasoning about size of types - be it in bytes or bits. For readability sake (and to reduce error space) we want to have an abstraction (probably based on some strong types) to model bit_size and byte_size as separate types.