Filter mouse wheel event in QComboBox of app parameters

Summary

In otbgui, block mouse wheel events of QComboBox widgets for choice parameters, and output image pixel type selection. This is to improve UX when scrolling in applications with many parameters. Scrolling in the list of parameters can result in a combo box taking the focus, and users accidentally changing a choice parameter or a numerical value.

Note that it's already in place for int and float parameters. This MR refactors the event filter in QtWidgetParameterBase so that any children can register it.

Copyright

The copyright owner is CNES and has signed the ORFEO ToolBox Contributor License Agreement.

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Check before merging:

• All discussions are resolved
• At least 2 votes from core developers, no vote.
• The feature branch is (reasonably) up-to-date with the base branch
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