Findfmt.cmake addition, master branch (2020.07.06.)

Made it possible to pick up fmt using its own CMake configuration.

To make this possible, lcg_wrap_find_module(...) had to be taught how to extract include and library paths from imported targets. Note that this is only needed for a correct runtime environment setup, it is not needed for the build itself to succeed. Later on a couple of other modules may be updated to make use of this functionality, but for now I didn't want to change more than needed.

This is meant to fix ATLINFR-3620.