Presets: search current directory for presets files
This is similar to #21331 (closed) but simpler. In the case where a presets file is not found in the source directory, CMake should look in the current directory. The current behavior is:
cmake -S src/lib_a -B build --list-presets
CMake Error: Could not read presets from /home/user/repos/myrepo/src/lib_a: File not found
The presets file seems to make more sense located in a project's root directory rather than be duplicated for each source directory that might be built separately.