[FEA]: Provide std::linalg accessors

[fbusato]

Is this a duplicate?

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Area

libcu++

Is your feature request related to a problem? Please describe.

cuda::std::linalg scaled_accessor and conjugated_accessor are fundamental for defining C++ linear algebra interfaces based on mdspan

Describe the solution you'd like

Provide cuda::std::linalg scaled_accessor and conjugated_accessor

Describe alternatives you've considered

No response

Additional context

No response

[bernhardmgruber]

Those are from paper: https://wg21.link/P1673r13