Set menu parents

[vkbo]

Summary:

This PR adds a parent item to all QMenu constructors. This can help with the positioning issue according to QTBUG-68636.

The remaining issue is a know issue with Qt5 on Wayland, and is not likely to be fixed. Moving to Qt6 (#1142) is the more likely solution, which will have to wait.

Related Issue(s):

Closes #1536

Reviewer's Checklist:

• The header of all files contain a reference to the repository license
• The overall test coverage is increased or remains the same as before
• All tests are passing
• All flake8 checks are passing and the style guide is followed
• Documentation (as docstrings) is complete and understandable
• Only files that have been actively changed are committed