[RFC]: add `lapack/base/dlange`

### Description

This RFC proposes to add `lapack/base/dlange`

### Related Issues

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### Questions

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### Other

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### Checklist

- [x] I have read and understood the [Code of Conduct](https://github.com/stdlib-js/stdlib/blob/develop/CODE_OF_CONDUCT.md).
- [x] Searched for existing issues and pull requests.
- [x] The issue name begins with `RFC:`.

Begin with the proposed lapack/base/dlange entry point. The RFC does not specify implementation details, tests, or acceptance criteria, so clarify the expected scope and definition of done with maintainers before coding.

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