Create first-timer issues for CMake cleanup of single use variables

[tylerjw]

There are places in our cmake files you can find lists that are defined in one place and used in only one other place. An example is THIS_PACKAGE_LIBRARIES in moveit_kinematics cmake file. Moving the values in the list to the one place the variable is used is a nice cleanup as it makes the cmake file more declarative, shorter, and easier to read.

To create opportunities for new contributors and be a good mentor:

• [ ] Find instances of this in our CMake files
• [ ] Create good-first-issue issue making reference to this issue. Make sure to add that label.
• [ ] Review PRs that people submit to do these cleanups
• [ ] Enjoy cleaning up MoveIt and helping new contributors!