As they do not look nice in the layouts and several
options pages are involved in the case of the form
class wizard.

Reviewed-by: con
Task-number: QTCREATORBUG-2778

Also move Designer::Internal::FormWindowEditor ->
Designer::FormWindowEditor.

Make Gui app wizard use Qt Designer wizard code to write the classes.
Remove the settings from the form class wizard page extension area and
add a settings page instead. Polish the designer plugin's structs to
parametrize class generation with QSharedData and settings code.
Export them and use them in the Gui app wizard.

Task-number: 256927

Fixes: Introduce a cpp settingspage containing file naming conventions (lower case and suffixes). Reorder VCS settings pages.

Task: 241959, 248085

RevBy: Optics/Naming checked by con
Details: Give IOptionPage an id() to differentiate from trName(). Make showOptionsDialog return a bool (applied) and give it an optional parent. Change Cpp and form class wizards, give them a Configure... button to change those settings.