[feature] Processing raster calc: add missing btns and validate

[elpaso]

Add missing buttons for ABS/MIN/MAX and validate expression.

[roya0045]

Do the 3 functions comes with parenthesis by default or does the user need to specify? Also auto englobing (select "str", hit 'Max', "str" -> Max("str") ), I'm not sure what it's called.

[elpaso]

@roya0045 there is nothing really new here, these buttons are already available since 3.10 in the main menu -> Raster -> Raster Calculator C++ implementation, I just ported them to the Python side and added the validation (which is also already available in the C++ raster calculator dialog).

I f you are looking for a pet project, refactoring a bit the C++ implementation in a way that we don't have to duplicate things in the Python side could be a nice one :)

[roya0045]

@roya0045 there is nothing really new here, these buttons are already available since 3.10 in the main menu -> Raster -> Raster Calculator C++ implementation, I just ported them to the Python side and added the validation (which is also already available in the C++ raster calculator dialog).

Yeah I saw the code afterward.

I f you are looking for a pet project, refactoring a bit the C++ implementation in a way that we don't have to duplicate things in the Python side could be a nice one :)

I don't think this endeavor would benefit my employer/myself, my PRs do but the delays are unpleasant.