refactor: update blas/ext/base/dapxsum to follow current project conventions

[nightknighto]

Resolves #1465 .

Description

This pull request refactors blas/ext/base/dapxsum to follow current project conventions.

Related Issues

Related issues #788 , #1152

This pull request:

• resolves [RFC]: refactor blas/ext/base/dapxsum to follow current project conventions #1465
• progresses Refactor and update existing extended base BLAS packages according to current project conventions #1152

Questions

Any questions for reviewers of this pull request?

No.

Other

Any other information relevant to this pull request? This may include screenshots, references, and/or implementation notes.

No.

Checklist

Please ensure the following tasks are completed before submitting this pull request.

• Read, understood, and followed the contributing guidelines.

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@stdlib-js/reviewers

[kgryte]

This file has mixed TABS and spaces. The indentation should be 2-space.

This file is also missing separate build configurations for benchmarks and examples. See, e.g., https://github.com/stdlib-js/stdlib/blob/develop/lib/node_modules/%40stdlib/blas/ext/base/dapxsumors/manifest.json.

[nightknighto]

Added the missing confs.
For the indentation thing, I've run the document formatting tool on the file and they all look 2-spaces indented. If still not the correct result, please let me know how to deal with it

[kgryte]

Thanks for working on this @Deadreyo. Left a few comments. I also believe that there are missing changes to test files and some other files in lib. E.g., see this recent PR: https://github.com/stdlib-js/stdlib/pull/1993/files. Once resolved, this PR should be good to move forward.

[nightknighto]

Updated missing changes in lib and test files

[Planeshifter]

Did a review and the changes look all good to me. Thank you for working on this, @Deadreyo.