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.

The previous interface wasn't sufficient to properly support the Apply
button, since it didn't separate applying the changes from the cleanup
phase.

Designer settings pages still need some fixing.

Fixes Apply button causing problems for certain plugins, for example the
QuickOpen.