Include section on onix acquisition clock

[ChucklesOnGitHub]

Not sure exactly where, maybe https://open-ephys.github.io/bonsai-onix1-docs/articles/getting-started/onix-acquisition.html
but make it explicit that multiple Clock members correspond to the same hw clock so that is what users should use to time-align, a note on the difference with HubClock and a warning related to the use of the Bonsai Timestamp node. These are common pitfalls.