Add SearchField for Qt Quick Controls

Add a QQuickSearchField to the list of Qt Quick Controls to make it easier to search from a list of items.

Suggestion

The search field would derive QQuickTextField, and have an API that supports searching from a list.

A potential API could look like this: 

// the model to search from
Q_PROPERTY(QQmlInstanceModel *delegateModel READ delegateModel NOTIFY delegateModelChanged FINAL)
// the delegate item to display for the list entry
Q_PROPERTY(QQmlComponent *delegate READ delegate WRITE setDelegate NOTIFY delegateChanged FINAL)
// popup in which to display the entries
Q_PROPERTY(QQuickPopup *popup READ popup WRITE setPopup NOTIFY popupChanged FINAL)
// if auto completion/suggestion should be enabled
Q_PROPERTY(bool autoSuggest READ autoSuggest WRITE setAutoSuggest NOTIFY autoSuggestChanged FINAL)

References

NSSearchField: https://developer.apple.com/documentation/appkit/nssearchfield
AutoSuggestBox: https://learn.microsoft.com/en-us/uwp/api/windows.ui.xaml.controls.autosuggestbox?view=winrt-26100

SearchBox: https://learn.microsoft.com/en-us/uwp/api/windows.ui.xaml.controls.searchbox?view=winrt-26100

Gtk SearchBar: https://docs.gtk.org/gtk4/class.SearchBar.html

QCompleter: https://doc.qt.io/qt-6/qcompleter.html
QComboBox

Plan for PoC

Try to implement a SearchField with QML

1. User needs to create a source model (will be in C++ most likely)
2. Filtering mechanism needs to be applied (e.g. QSFPM). Remains to be seen if QSFPM should be public, but atm it doesn't exist in QML (but is planned).
3. Visualization of the filtering can be done either by a built-in popup window (with a ListView), or the application can choose to visualize the filtered content themselves in a separate ListView that has its model bound to the SearchField.proxyModel (e.g. SearchField on macOS settings does filtering). Whether the search field should automatically popup a window, can be controlled by a property on search field.
4. Icons: Search + cancel Icon

Other things to consider:

1. Can visualization also be inline? (e.g. QCompleter::InlineCompletion)
2. Keyboard navigation: Does focus need to be transferred from the SearchField to the ListView if e.g. pressing arrow down?