Alter class to provide formatting for different rules/themes

[BrianCriswell]

Starting a discussion here for how to support different themes and systems.

Systems are different sets of rules for playing a TTRPG

• D&D in each of its flavors (5e 2014, 5e 2024, 3.5, 4e, etc.)
• Pathfinder (1e and 2e)
• Starfinder (1e and 2e)
• and so on

Themes are different ways of expressing and formatting the information of the system. Within a group of themes for a system, the content might not change but its layout might. As an example, the dndbook class currently has a default theme based on 2014 books. I made my own custom theme for War of the Burning Sky . An Eberron-themed book might want to more closely follow the theming of an official Eberron book.

The dndbook class should be modified to be able to handle switching between the more crunchy bits of rules at a document level. This probably means some restructuring of the underlying file organization.

It also should make it as easy as possible to switch up the theming of a rule system (although I am not sure what else can be done at a low level). Maybe there is room to make it easier to encapsulate the elements of a theme together.