Move `tracy_set_option` and `tracy_set_option_value` from `CMakeLists.txt` into `cmake/options.cmake`. Add `tracy_set_option_value_as_string` for options whose value is embedded as a C string literal. All three accept an optional trailing target argument; when provided, the option is also propagated as a PUBLIC compile definition on that target.
Existing `set_option`/`set_option_value` are unchanged but will be replaced later by the `tracy_*` versions.