Create Squish test suite and UI tests

Create new test suite that will run the UI tests (e.g. suite_application_examples) in suites/packaging-directory.

Use any Qt6 version (6.5.1 might be most stable) and any platform. Use the highlighted_apps suite as an example, so that there is clear parts in test cases: first part/section for compiling the example and doing target specific initializations (hooking in Android and B2Qt), this is where all the if-elses will be when test coverage is expanded. Second part which will do the actual UI testing and will be common for all (as far as it's possible).

Also, the first test case should only do installation, use "default" mode for product_qt, so binaries and all additional modules will be installed. No Creator installation needed.

One test case for each example.