Add integer datatypes and add types to tests

[AlexanderKalistratov]

• Add integer dtypes (int8,int16, uint8-uint64) to dpnp interface
• Add missing aliases to integer types: [u]byte, ushort, [u]longlong
• Not adding [u]long aliases as it is removed from NumPy (https://numpy.org/devdocs/release/1.20.0-notes.html#deprecations)
• Removed int alias as it is depricate in NumPy
• Extend tests types matrix by these types
• Add environment variable DPNP_TEST_ALL_INT_TYPES to enable/disable these types in tests

Failing dpnp tests:

test_arraycreation.py::test_geomspace
test_arraycreation.py::test_linspace
test_arraycreation.py::test_logspace
test_fft.py::TestFft2::test_fft2
test_fft.py::TestRfft2::test_rfft2
test_histogram.py::TestDigitize::test_digitize
test_indexing.py::TestPut::test_input_1d
test_indexing.py::TestPut::test_input_2d
test_indexing.py::TestPutAlongAxis::test_replace_max
test_indexing.py::TestTake::test_1d
test_indexing.py::TestTake::test_2d
test_indexing.py::TestTakeAlongAxis::test_broadcast
test_indexing.py::TestTakeAlongAxis::test_empty
test_indexing.py::TestTakeAlongAxis::test_empty
test_indexing.py::TestTakeAlongAxis::test_multi_dimensions
test_linalg.py::TestCond::test_cond
test_linalg.py::TestEigenvalue::test_eigenvalues
test_linalg.py::TestLstsq::test_lstsq_diff_type
test_linalg.py::TestNorm::test_norm_1D
test_linalg.py::TestNorm::test_norm_2D
test_linalg.py::TestNorm::test_norm_ND
test_linalg.py::TestNorm::test_norm_usm_ndarray
test_linalg.py::TestPinv::test_pinv
test_linalg.py::TestQr::test_qr
test_linalg.py::TestSvd::test_svd
test_manipulation.py::TestUnique::test_2d_axis_signed_inetger
test_manipulation.py::test_copyto_dtype
test_mathematical.py::TestAngle::test_angle
test_mathematical.py::TestCumLogSumExp::test_basic
test_mathematical.py::TestCumProd::test_out_dtype
test_mathematical.py::TestCumSum::test_out_dtype
test_mathematical.py::TestFix::test_basic
test_mathematical.py::TestFix::test_out
test_mathematical.py::TestHypot::test_hypot
test_mathematical.py::TestLogSumExp::test_logsumexp
test_mathematical.py::TestLogSumExp::test_logsumexp_dtype
test_mathematical.py::TestLogSumExp::test_logsumexp_out
test_mathematical.py::TestLogSumExp::test_logsumexp_out_dtype
test_mathematical.py::TestMathematical::test_remainder
test_mathematical.py::TestMatmul::test_matmul_axes_ND_ND
test_mathematical.py::TestMatmul::test_matmul_axes_out
test_mathematical.py::TestMatmul::test_matmul_dtype
test_mathematical.py::TestMatmul::test_matmul_dtype_matrix_inout
test_mathematical.py::TestMatmul::test_matmul_dtype_matrix_inputs
test_mathematical.py::TestMatmul::test_matmul_out1
test_mathematical.py::TestMatmul::test_matmul_out2
test_mathematical.py::TestPower::test_basic
test_mathematical.py::TestProd::test_prod_out_dtype
test_mathematical.py::TestReduceHypot::test_reduce_hypot
test_mathematical.py::TestReduceHypot::test_reduce_hypot_dtype
test_mathematical.py::TestReduceHypot::test_reduce_hypot_out
test_mathematical.py::TestUnwrap::test_discont
test_mathematical.py::TestUnwrap::test_rand_period
test_nanfunctions.py::TestNanProd::test_nanprod_out_dtype
test_product.py::TestDot::test_dot
test_product.py::TestDot::test_dot_ndarray
test_product.py::TestDot::test_dot_out
test_product.py::TestDot::test_dot_out_scalar
test_product.py::TestDot::test_dot_scalar
test_product.py::TestInner::test_inner
test_product.py::TestInner::test_inner_scalar
test_product.py::TestKron::test_kron_scalar
test_product.py::TestMultiDot::test_multi_dot
test_product.py::TestMultiDot::test_multi_dot_all_2d
test_product.py::TestMultiDot::test_multi_dot_out
test_product.py::TestTensordot::test_tensordot
test_product.py::TestTensordot::test_tensordot_axes
test_product.py::TestTensordot::test_tensordot_input_dtype_matrix
test_product.py::TestTensordot::test_tensordot_scalar
test_sort.py::test_partition
test_statistics.py::TestAverage::test_avg
test_statistics.py::TestAverage::test_avg_strided
test_statistics.py::TestStd::test_std_strided
test_statistics.py::TestVar::test_var_strided
test_statistics.py::test_median
test_strides.py::test_cumlogsumexp
test_strides.py::test_logsumexp
test_strides.py::test_reduce_hypot
test_strides.py::test_strides_erf
test_sum.py::test_sum
test_umath.py::TestArctan2::test_arctan2
test_umath.py::TestCbrt::test_cbrt
test_umath.py::TestCopySign::test_copysign
test_umath.py::TestFloatPower::test_negative_base_value_complex_dtype
test_umath.py::TestLogAddExp::test_logaddexp
test_umath.py::TestRsqrt::test_rsqrt
test_umath.py::TestUmath::test_out

[AlexanderKalistratov]

@antonwolfy

[antonwolfy]

We need to update the list of supported type in documentation, please check doc/reference/dtypes_table.rst

[antonwolfy]

Thank you @AlexanderKalistratov, LGTM!