Consolidate methods and standardize units for calculating saturated vapor pressure deficit

[dlebauer]

consolidate get.es, SatVapPres functions and a new method proposed in #3590 into a single saturated_vapor_pressure function with args

❓ is there a preferred method to use as default?

#' @param method c("Magnus","ClausiusClapeyron","GoffGratch")
#' @param temp_units input temperature units ("degC","K","degF"), default "degC"
#' @param out_units output pressure units ("kPa","hPa","Pa","mb"), default "kPa"

Review Time Estimate

• Immediately: so it can be used in enhance met downscaling with adding a support for soil temp, RH, soil moisture, PPFD and refactored to address other critical issues #3590
• Within one week
• When possible

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My change requires a change to the documentation.
• My name is in the list of CITATION.cff
• I agree that PEcAn Project may distribute my contribution under any or all of
  • the same license as the existing code,
  • and/or the BSD 3-clause license.
• I have updated the CHANGELOG.md.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

[infotroph]

Needs Roxygen run and I see one logger call that will never fire, but otherwise looks good

[infotroph]

FTR match.arg will handle this case for you by erroring on no match, so this logger call will never fire.

[dlebauer]

Cool, thanks!