[ndgrigorian]

This PR removes the legacy RNG implementation of dpnp.random from dpnp_backend_c, along with the newly-dead code in the backend, as the last part of the series splitting #3147. It is stacked on #3162

Removes

• The dpnp_algo_random Cython module, the backend RNG kernels, DPNPRandomState, the DPNP_FN_RNG_* function pointers and the mt19937/mcg59 engines of backend_sycl
• The backend's C++ examples, its GTest suite and the DPNP_BACKEND_TESTS CMake option
• The NumPy fallback helper call_origin and the other helpers that only the RNG used
• The onemkl-sycl-rng pin in the conda recipes

dpnp_backend_c itself stays, since dpnp.partition still uses it (#3138 removes that)

• Have you provided a meaningful PR description?
• Have you added a test, reproducer or referred to an issue with a reproducer?
• Have you tested your changes locally for CPU and GPU devices?
• Have you made sure that new changes do not introduce compiler warnings?
• Have you checked performance impact of proposed changes?
• Have you added documentation for your changes, if necessary?
• Have you added your changes to the changelog?

[github-actions]

Array API standard conformance tests for dpnp=0.22.0dev0=np2py314h8d9cdd5_33 ran successfully.
Passed: 1491
Failed: 0
Skipped: 6

[coveralls]

Coverage is 82.849% — feature/remove-legacy-rng into feature/device-rng-random-state. No base build found for feature/device-rng-random-state.

[github-actions]

View rendered docs @ https://intelpython.github.io/dpnp/pull/3163/index.html