Re-implement essl_colorized_low_level_moisture using colorize

[gerritholl]

Feature Request

Is your feature request related to a problem? Please describe.

The composite essl_colorized_low_level_moisture is currently implemented using a dedicated enhancement class in satpy.enhancements.atmosphere.py:

satpy/satpy/enhancements/atmosphere.py

Line 24 in 7a0dc1a

def essl_moisture(img, low=1.1, high=1.6) -> None:

However, this does nothing else than calculating a colormap. Therefore, this could be some simply defined using colorize. This would be easier to maintain or modify. Moreover, the current enhancement function only works for mode L input data, not LA, and can therefore not be used with input coming from MaskingCompositor. This makes it hard to overlay a cloud mask or a land/water mask. Another problem is that the ratio is defined the opposite way compared to the original design by Hans-Peter Roesli.

Describe the solution you'd like

I would like to re-implement essl_colorized_low_level_moisture as a RatioCompositor with a colorize enhancement.

Describe any changes to existing user workflow

This will break any user's workflow that relies on the essl_moisture function being present.

Additional context

An alternative would be to adapt the essl_low_level_moisture function to work with LA input data, but this would only solve part of the problem.