feat(pricing, types): PriceSets as entry point to pricing module (#4978)

What:
- Adds PriceSet, PriceSetMoneyAmount, updates schema
- Adds service/repo for PriceSet
- Shifts entry point to use PriceSet
- Updates link/joiner config

RESOLVES CORE-1495

packages/pricing/tsconfig.spec.json

@@ -1,5 +1,8 @@
 {
   "extends": "./tsconfig.json",
   "include": ["src", "integration-tests"],
-  "exclude": ["node_modules", "dist"]
+  "exclude": ["node_modules", "dist"],
+  "compilerOptions": {
+    "sourceMap": true
+  }
 }