Update fundamental constants with 2019 redefinition by BIPM

[PeterC-DLS]

See https://www.bipm.org/en/measurement-units/si-defining-constants and the 9th edition of the SI Brochure

[keilw]

We have a couple of those, but not every single one I recall:

• [x] the caesium hyperfine frequency ΔνCs
• [x] the speed of light in vacuum c
• [x] the Planck constant h
• [x] the elementary charge e
• [x] the Boltzmann constant k
• [x] the Avogadro constant NA, and
• [x] the luminous efficacy of a defined visible radiation Kcd

[PeterC-DLS]

Elementary charge and speed of light are used too in several places in SI and NonSI classes.

[keilw]

Thanks @PeterC-DLS, with 2.2 this constant graduated to SI marking it for removal in NonSI in a future version.