add react template docs or consolidate template-specific docs

[frolic]

I don't really think we need to document each template if we can just provide instructions on how to create from a template, then can let the CLI do the explaining (it currently doesn't, but we could improve this).

Otherwise we should at least add a page for the React template so folks use that over the React ECS one (currently the only React one in docs)

[linear]

MUD-8 add react template docs or consolidate template-specific docs