Update dpnp.linalg.eig/eigvals

[vlad-perevezentsev]

This PR proposes to update dpnp.linalg.eig() and dpnp.linalg.eigvals() functions using numpy call.
Using numpy.linalg.eig/eigvals is a temporary solution until MKL implements oneapi::mkl::lapack::geev for USM interface.

This PR also removes dpnp_algo_linalg.pyx file because it no longer contains Cython functions

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[vlad-perevezentsev]

@antonwolfy also I would also remove the backend implementation of dpnp_eigvals_c and dpnp_eig_c cause it is only implemented for symmetric arrays which is wrong.
What do you think about this?

[antonwolfy]

@antonwolfy also I would also remove the backend implementation of dpnp_eigvals_c and dpnp_eig_c cause it is only implemented for symmetric arrays which is wrong. What do you think about this?

We definitely need to plan a clean up, but I would prefer to do that by a separate PR (like to remove all unused linalg functions from backend at once and so on). But needs to be careful to avoid an unexpected impact on numba-dpex.

[github-actions]

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[antonwolfy]

LGTM! Thank you @vlad-perevezentsev