Add ambient dose coefficients (H*(10)) from ICRP74

[MatteoZammataro]

Description

This pull request is in response to issue #3216, and is a supplement to PR #3020. The goal is to allow the user to use H*(10) dose coefficients in addition to the effective dose coefficients which were previously available.
I've created a folder called ambient_dose_coefficients on openmc.data, in which I've defined the function ambient_dose_coefficients(). The previous function dose_coefficients() has been renamed effective_dose_coefficients(). I have kept the same folder architecture used in effective_dose in case there is a possibility to add more coefficients from different data sources.

Checklist

• I have performed a self-review of my own code
• I have followed the style guidelines for Python source files
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works