Update logging events section with server and client side logs and reason to do this

[underscorefunk]

Add preamble to logging to explain why we're starting with witnessing and event a logging an event.

Then use a simpler server side log.
Then add a client side log with simpler logging method

Then explain how the logging would work with web_sys

[underscorefunk]

Also highlight how this would be done with vanilla javascript as an aside. i.e. "How we'd do this with the web platform exclusively". Maybe this is beyond scope of the document though.