Sushi!

Soy sauce and horseradish are found with other condiments - fastfood,
dining, and kitchen.
Cookbook is found in homebooks and kitchen groups.
Food is craftable-only until we get a sushi restaurant *HINT* where we
can spawn these things in a special item group.
Tweak.
Tweak.
Book spawn tweak.
Servings tweak.
Merge pull request #9042 from Rivet-the-Zombie/sushi

Sushi!