Refactor/code reorganization

[diptorupd]

• Have you provided a meaningful PR description?
  Some small code reorganization changes extracted out of Code reorganization: Removes ocl kernel API, moves math, print into kernel_api_impl #1420
• Have you tested your changes locally for CPU and GPU devices?
• Have you made sure that new changes do not introduce compiler warnings?

[coveralls]

coverage: 85.177% (+0.4%) from 84.823%
when pulling 1cde85e on refactor/code-reorganization
into 013be2e on main.

[ZzEeKkAa]

Thank you