Add page about time alignment with brain_observatory_utilities

[matchings]

Every year at SWDB, I end up needing to direct students to brain_observatory_utilities to help them with time alignment for Visual Behavior data so they can get event aligned traces without spending an entire day writing code to do it. I think there should be a page in the databook (maybe in a “tools” section?) describing the purpose of this repo and how to use the main functions.

Down the line as we switch fully to pynwb for VB datasets we will need to update BOU to be compatible with non-SDK organized inputs.