Fix commutator page

[cjsha]

I think the presentation of the commutator on this page could be more impressive. I propose putting a video of a coax commutator demo with a brief description.

Plus, it repeats info that is already maintained in the commutator docs. I think that info should be removed, keeping only a brief description, and say something like:

For more information, visit the `commutator docs <https://open-ephys.github.io/commutator-docs/>`_.