ENH: Improve QGIS field parameter selection
This MR follows !767 (merged) and !768 (merged) to improve parameter selection in QGIS.
It replaces some ParameterListView with ParameterType_Field and ParameterType_InputFilename with ParameterType_InputVectorData when relevant.
These modifications were delayed in order to wait for QGIS 3.18 release which embed this PR. It indeed needs the support of field selection for MultipleLayers in TrainImagesClassifier (which is a composite of the other modified applications)
I would like to update QGISInterface.rst but I'm not sure in which OTB version this modification will land (8.0 ? 8.1.0?).