Improve Header File Specification Using File Sets

[threeal]

This issue suggests adopting file sets instead of using include directories to specify headers. Refer to this documentation for more details on utilizing file sets as a modern CMake approach for setting header files.

While setting file sets may be more complex than using include directories, it promotes better practices for manually specifying source files, including headers, for a specific target.

Additionally, using file sets allows only the relevant header files for the target to be installed, rather than installing the entire directory, which is beneficial for addressing #62.