Replace documentation pages with updated PolicyEngine Core tools

Removing reform code where unnecessary, and using the `Simulation` interface, will speed up the build time (currently 15 minutes).

Start by locating the documentation pages and reform code referenced in the issue, then trace how the Simulation interface is used. Confirm the current build time before making changes; done means unnecessary reform code is removed, the updated PolicyEngine Core tools are documented, and the build is faster than the current 15 minutes.

Written by the indexing model from the issue text.