Migrate PlaygroundLogger's module map files from a Copy Files phase to the MODULEMAP_FILE and MODULEMAP_PRIVATE_FILE build settings.

Xcode natively understands module maps, so it's better to use that support directly instead of doing something custom.
This prevents issues building PlaygroundLogger with the new build system in Xcode 9.

This addresses <rdar://problem/34019263>.

Author: iOSdev0623