Added chainable wxWizardPageSimple::Chain() overload.

Add the simplest and most fool proof of chaining the pages in static wizards:
just chain several calls to the new, non-static, wxWizardPageSimple::Chain()
overload.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@73806 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775