Adapt "Qt for Linux/X11 - Deployment" to CMake + Qt 6

https://doc.qt.io/qt-6/linux-deployment.html needs improvements:

• First paragraph mentions AIX, Irix, which are not supporte anymore. They are also Unixes (and the page continues to talk about Unix), though the page should be about Linux specifically?
• Building Qt statically section suggests using make, instead of ninja or cmake --build . . It should also link to https://doc.qt.io/qt-6/linux-building.html . Finally, I do think Qt Designer is built even for -static? To be verified.
• Linking the Application to the Static Version of Qt and Linking the Application to Qt as a Shared Library sections are qmake specific. They should also mention cmake.
• "Application Dependencies" goes to the Windows page. It should link to the section on the same page instead.