feat: add C `ndarray` API and refactor `blas/ext/base/dnannsumkbn`

[headlessNode]

Resolves none.

Description

What is the purpose of this pull request?

This pull request:

• Adds C ndarray API and refactor/cleanup blas/ext/base/dnannsumkbn

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No.

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• [x] Read, understood, and followed the contributing guidelines.

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@stdlib-js/reviewers

[headlessNode]

The failing test is from dnannsum which uses dnannsumkbn to compute the sum. It will be resolved once dnannsum is refactored.

[headlessNode]

@kgryte Using CBLAS_INT is causing the format specifier error. I think we will need to define format specifiers for CBLAS_INT.

EDIT: Just saw that it is defined. Sorry for the oversight.

[kgryte]

@headlessNode Based on feedback in the other PRs, does this PR need some further tweaks?

[stdlib-bot]

Coverage Report

Package	Statements	Branches	Functions	Lines
blas/ext/base/dnannsumkbn	$\color{green}491/491$ $\color{green}+100.00\%$	$\color{green}42/42$ $\color{green}+100.00\%$	$\color{green}4/4$ $\color{green}+100.00\%$	$\color{green}491/491$ $\color{green}+100.00\%$

The above coverage report was generated for the changes in this PR.

[headlessNode]

@kgryte ready for review.

[kgryte]

@headlessNode This PR has a failing test atm.

[headlessNode]

@kgryte the failing test is expected.

[kgryte]

Ah, right. It is a downstream test suite which is failing.

[kgryte]

As mentioned in https://github.com/stdlib-js/stdlib/pull/2988#issuecomment-2484947084, the CI test failure in the downstream library is expected. This failure will be resolved in a subsequent PR/commit. As such, I will go ahead and merge.