Support NIRSport devices #7922
Description
Currently, mne.io.read_raw_nirx has been thoroughly tested only with data from NIRScout. However, we should add support for the other two devices from the company (NIRSport and the newer NIRSport2). As mentioned in #7894 and #7905, most generated files differ between devices except for the raw intensities (.wl1 and .wl2) so that we need to adapt the current reader accordingly. Test recordings for both devices are available in #7905.