This commit fixes error like the following:

```
Requested modules not available:

    WikiExamples
```

The commit lorensen/VTKExamples@3da258b fixes the configuration and build
of VTKWikiExamples as both a VTK remote module and a stand-alone project.
It ensure **first and follow-up configurations** produce similar results
and behave **identically**.

The build was broken following the introduction of
Kitware/VTK@e33b90d (ExternalModule: Improve target export to
allow build against external module).

The commit addresses the issue by introducing the WikiModuleConfig CMake
module responsible for:

* ensuring module information are exported into `VTK_MODULES_DIR` by using
`vtk_module_export_info`.

* using `vtk_module_config` to ensure that variables like `VTK_LIBRARIES`
are set in the current scope when the project is build.

* ensuring required compile definitions (i.e. <module>_AUTOINIT macros
needed for object factory overrides initialization) are used.

Co-authored-by: Bill Lorensen <bill.lorensen@gmail.com>