Add diagnostic to calculate hour of maximum precipitation

[schlunma]

Description

This PR adds a diagnostic and example recipe to calculate the maximum hour of precipitation. The following methods can be selected in the recipe:

• If "dft", apply a discrete Fourier transform (DFT) to the data and use the peak of the first component (see https://mdtf-diagnostics.readthedocs.io/en/latest/sphinx_pods/precip_diurnal_cycle.html).
• If "harmonic_fit", fit a 12hr- plus 24hr-harmonic to the input data and use the peak of the 24hr-harmonic (see Dai, 2024; https://doi.org/10.1007/s00382-024-07182-6). This should give identical/very similar results to "dft", but is much slower.
• If "max", simply use the maximum in the input data.

• Link to documentation:

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[schlunma]

Doc build fail not related to this PR: #4333

[LisaBock]

I get this error message from the diagnostic: AttributeError: module 'numpy' has no attribute 'atan2'. Did you mean: 'arctan2'?
@schlunma Do you know about this issue?

[schlunma]

Interesting, maybe it's because of an old version of numpy. numpy.atan2 actually exists: https://numpy.org/doc/stable//reference/generated/numpy.atan2.html.

Nevertheless, I replaced it with arctan2 in the code because the handling of special input values seems to be better.

[LisaBock]

Works fo me now! Thanks!