feat: masking-filter based on other fields in the dataset

[mpvginde]

Description

Adds apply_mask_from_field, a companion to the existing apply_mask_fields filter.
Where apply_mask_fields loads a mask from an external file, apply_mask_from_field derives the mask from another field already present in the data pipeline (e.g. a land-sea mask sourced alongside the other variables).

Usage:

        input:
          pipe:
            - source: # Can be `mars`, `netcdf`, etc.
               param: [lsm, sst, ...]
            - apply_mask_from_field:
                mask_param: lsm
                param: [sst]
                threshold_operator: ">=" # Operator to use for thresholding
                threshold: 0.5 # Will set to NaN all values where mask >= 0.5

Masked points are set to NaN. An optional rename suffix can be appended to the output param name.
The filter passes mask_param and any other non-targeted fields through unchanged.

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[mpvginde]

This functionality is already covered in #277

[aaron-hopkinson]

Great minds think alike, @mpvginde, @mc4117 😉