Spectral responsivity and quantum efficiency conversion functions

[echedey-ls]

Is your feature request related to a problem? Please describe.
Add functions to convert from SR to EQE and vice versa.

Describe the solution you'd like
Two distinct functions for each one of the purposes, that work both with pandas.Series and vector inputs.

Describe alternatives you've considered
N/A.

Additional context
Initially proposed by @markcampanelli in #1963.