NIST SP 811: Add NIST acceptable constants often used as units with SI

<img width="941" alt="Image" src="https://github.com/user-attachments/assets/6cec383a-7ac9-40f3-84e4-e147d5bdd6f8" /> 

 _Originally posted by @ronaldtse in [#2](https://github.com/unitsml/unitsdb/issues/2#issuecomment-2732016585)_