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/integration-tests/__fixtures__/price-set/data.ts

@@ -0,0 +1,13 @@
+import { CreatePriceSetDTO } from "@medusajs/types"
+
+export const defaultPriceSetsData = [
+  {
+    id: "price-set-1",
+  },
+  {
+    id: "price-set-2",
+  },
+  {
+    id: "price-set-3",
+  },
+] as unknown as CreatePriceSetDTO[]

packages/pricing/integration-tests/__fixtures__/price-set/index.ts

@@ -0,0 +1,38 @@
+import { CreatePriceSetDTO } from "@medusajs/types"
+import { SqlEntityManager } from "@mikro-orm/postgresql"
+import { PriceSet, PriceSetMoneyAmount } from "@models"
+import { defaultPriceSetsData } from "./data"
+
+export async function createPriceSets(
+  manager: SqlEntityManager,
+  priceSetsData: CreatePriceSetDTO[] = defaultPriceSetsData
+): Promise<PriceSet[]> {
+  const priceSets: PriceSet[] = []
+
+  for (let priceSetData of priceSetsData) {
+    const priceSetDataClone = { ...priceSetData }
+    const moneyAmountsData = priceSetDataClone.money_amounts || []
+    delete priceSetDataClone.money_amounts
+
+    let priceSet = manager.create(PriceSet, priceSetDataClone) as PriceSet
+
+    await manager.persist(priceSet).flush()
+
+    for (let moneyAmount of moneyAmountsData) {
+      const price_set = (await manager.findOne(
+        PriceSet,
+        priceSet.id
+      )) as PriceSet
+
+      const psma = manager.create(PriceSetMoneyAmount, {
+        price_set: price_set.id,
+        money_amount: moneyAmount.id,
+        title: "test",
+      })
+
+      manager.persist(psma).flush()
+    }
+  }
+
+  return priceSets
+}