build: Add cmake files for building the tests
* CMakeLists.txt: Add subdirectory tests to the build. * cmake/modules/G10CMakeSettings.cmake: Add option BUILD_TESTING. * tests/CMakeLists.txt: New. * tests/Makefile.am: Remove. * tests/README: Update.
This change adds support for building and running the test/example
programs.
- GnuPG-bug-id: T7262