Outline expressions so devs have a framework for optimizing their chalk apps

[elviskahoro]

Chalk apps get accelerated and optimized, see: https://docs.chalk.ai/docs/architecture#online-computation-and-serving

It'd be helpful if there was a page on expressions with a short blurb on what expressions are and some of their design patterns.

A few before and after examples to help devs recognize when a computation could be re-written so it can be auto-accelerated!