Renovate QWheelEvent in Gui

[YakoYakoYokuYoku]

Thanks for submitting a pull request! Please provide enough information so that others can review your pull request. Additionally, make sure you've done all of these things:

• I've followed the contributing guidelines to the best of my understanding
• I've read and understood the contributing guidelines
• I've formatted my code according to Natron's code style
• I've searched the pull requests tracker to ensure that this PR is not a duplicate

PR Description

What type of PR is this? (Check one of the boxes below)

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Improvement (non-breaking change which does not add functionality nor fixes a bug but improves Natron in some way)
• Breaking change (fix or feature that would cause existing functionality to change)
• My change requires a change to the documentation
  • I have updated the documentation accordingly

What does this pull request do?

QWheelEvent has many deprecated members in Qt 5 and usages like deltas, horizontal scrolls or positions are replaced with methods that returns QPoints that hold the relevant values.

Show a few screenshots (if this is a visual change)

N/A.

Have you tested your changes (if applicable)? If so, how?

Built Natron and used the node graph editor.

Futher details of this pull request

N/A.

[devernay]

What OS are you testing this on? Are you also testing on a laptop with a multi-touch trackpad that allows scrolling (for testing the wheel events)

[devernay]

Also, are you testing the Qt5 version on a hiDPI display? linux, mac, windows? I had to fix something for retina on macOS, and wanted to be sure it didn't break others.
BTW we may have to release a 2.6 alpha with Qt5 soon, at least on macOS, because Qt4 is invariably crashing on macOS Monterey

[YakoYakoYokuYoku]

I'm testing this on Solus, a Linux desktop distro. At the moment I'm with my PC tower only so I cannot test with a laptop. Also my monitor DPI has 96 dots per inch so no validations with hiDPI either.

[YakoYakoYokuYoku]

If we want to release an alpha sooner I'll start volleying other commits that I have in my local branch.