CORE-1161 - Super documents

[TylerZeroMaster]

https://openstax.atlassian.net/browse/CORE-1161

Add basic recipe for super documents. This is still kind of a skeleton, but it serves as a MVP that can be built upon.

Note: the original idea was to exclude the ToC in baking, however, later parts of the pipeline depend on the baked ToC. Instead of excluding it here, it will continue to be removed in the step-prepare-ancillaries step.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (beaff0f) to head (526583e).
⚠️ Report is 1 commits behind head on main.

@@            Coverage Diff            @@
##              main      #418   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files          219       219           
  Lines         3681      3687    +6     
=========================================
+ Hits          3681      3687    +6     

Files with missing lines	Coverage Δ
lib/kitchen/directions/bake_learning_objectives.rb	100.00% <100.00%> (ø)
...move_solutions_to_answer_key/answer_key_cleaner.rb	100.00% <100.00%> (ø)

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[RoyEJohnson]

This looks reasonable to me, but I'm not familiar with this repo. You might want to have someone else look it over, as well.