Add CMake files as alternatives to qmake files in uitools/

[pbegun]

Addressing these posts:

• Can't Install Toolkit in a CMake Project
• https://github.com/Esri/arcgis-maps-sdk-toolkit-qt/issues/602

I translated toolkitcpp.pri, toolkitwidgets.pri, and common.pri into CMake files so that they can be used with CMake projects. (I didn't bother with toolkitqml.pri, since ArcGIS will not be supporting the QML API much longer.) I also updated the README to include instructions on how to use these files.

@ldanzinger , can you please review or assign a reviewer? Thanks in advance!

[ldanzinger]

Thanks for this @pbegun! We are finishing up some certification testing for our upcoming 200.4 release. I hope to get someone on this shortly.

[JamesMBallard]

Hi @pbegun. Thanks for putting this together. Our team did some testing and found some minor issues. We're a bit tight on time at the moment, but we plan to do the work to enable CMake in the toolkit for our next release. We may use your PR/branch as a starting point for the work.

[pbegun]

Thanks @JamesMBallard & @ldanzinger! That's fine by me :)