data: Add a top level wrapper for `Linker`. The `family` object is special in that it's "attached" to the current page, so make an object dedicated to that. It removes special code in `Linker`, and makes it possible to go `family.children` directly to get a page's children (i.e. pages in a directory of the same name).

@echo off
setlocal

set CUR_DIR=%~dp0
set CHEF=%CUR_DIR%..\bin\chef
set OUT_DIR=%CUR_DIR%..\piecrust\resources\messages
set ROOT_DIR=%CUR_DIR%messages

%CHEF% --root=%ROOT_DIR% bake -o %OUT_DIR%
del %OUT_DIR%\index.html