Remove binder links for static notebooks

[f-brinkmann]

The static notebooks have binder links - they probably should not have them

• https://pyfar-gallery.readthedocs.io/en/latest/gallery/static/impulse_response_measurement.html
• https://pyfar-gallery.readthedocs.io/en/latest/gallery/static/binaural_synthesis.html

[f-brinkmann]

closed by #58