feat(link-modules,modules-sdk, utils, types, products) - Remote Link and Link modules (#4695)

What:
- Definition of all Modules links
- `link-modules` package to manage the creation of all pre-defined link or custom ones

```typescript
import { initialize as iniInventory } from "@medusajs/inventory";
import { initialize as iniProduct } from "@medusajs/product";

import {
  initialize as iniLinks,
  runMigrations as migrateLinks
} from "@medusajs/link-modules";

await Promise.all([iniInventory(), iniProduct()]);


await migrateLinks(); // create tables based on previous loaded modules

await iniLinks(); // load link based on previous loaded modules

await iniLinks(undefined, [
  {
    serviceName: "product_custom_translation_service_link",
    isLink: true,
    databaseConfig: {
      tableName: "product_transalations",
    },
    alias: [
      {
        name: "translations",
      },
    ],
    primaryKeys: ["id", "product_id", "translation_id"],
    relationships: [
      {
        serviceName: Modules.PRODUCT,
        primaryKey: "id",
        foreignKey: "product_id",
        alias: "product",
      },
      {
        serviceName: "custom_translation_service",
        primaryKey: "id",
        foreignKey: "translation_id",
        alias: "transalation",
        deleteCascade: true,
      },
    ],
    extends: [
      {
        serviceName: Modules.PRODUCT,
        relationship: {
          serviceName: "product_custom_translation_service_link",
          primaryKey: "product_id",
          foreignKey: "id",
          alias: "translations",
          isList: true,
        },
      },
      {
        serviceName: "custom_translation_service",
        relationship: {
          serviceName: "product_custom_translation_service_link",
          primaryKey: "product_id",
          foreignKey: "id",
          alias: "product_link",
        },
      },
    ],
  },
]); // custom links
```

Remote Link

```typescript
import { RemoteLink, Modules } from "@medusajs/modules-sdk";

// [...] initialize modules and links

const remoteLink = new RemoteLink();

// upsert the relationship
await remoteLink.create({ // one (object) or many (array)
  [Modules.PRODUCT]: {
    variant_id: "var_abc",
  },
  [Modules.INVENTORY]: {
    inventory_item_id: "iitem_abc",
  },
  data: { // optional additional fields
    required_quantity: 5
  }
});

// dismiss (doesn't cascade)
await remoteLink.dismiss({ // one (object) or many (array)
  [Modules.PRODUCT]: {
    variant_id: "var_abc",
  },
  [Modules.INVENTORY]: {
    inventory_item_id: "iitem_abc",
  },
});

// delete
await remoteLink.delete({
  // every key is a module
  [Modules.PRODUCT]: {
    // every key is a linkable field
    variant_id: "var_abc", // single or multiple values
  },
});

// restore
await remoteLink.restore({
  // every key is a module
  [Modules.PRODUCT]: {
    // every key is a linkable field
    variant_id: "var_abc", // single or multiple values
  },
});

```

Co-authored-by: Riqwan Thamir <5105988+riqwan@users.noreply.github.com>

packages/link-modules/src/migration/index.ts

@@ -0,0 +1,78 @@
+import {
+  JoinerRelationship,
+  LoaderOptions,
+  Logger,
+  ModuleJoinerConfig,
+  ModuleServiceInitializeOptions,
+} from "@medusajs/types"
+import { generateEntity } from "../utils"
+
+import { DALUtils, ModulesSdkUtils } from "@medusajs/utils"
+
+export function getMigration(
+  joinerConfig: ModuleJoinerConfig,
+  serviceName: string,
+  primary: JoinerRelationship,
+  foreign: JoinerRelationship
+) {
+  return async function runMigrations(
+    {
+      options,
+      logger,
+    }: Pick<
+      LoaderOptions<ModuleServiceInitializeOptions>,
+      "options" | "logger"
+    > = {} as any
+  ) {
+    logger ??= console as unknown as Logger
+
+    const dbData = ModulesSdkUtils.loadDatabaseConfig("link_modules", options)
+    const entity = generateEntity(joinerConfig, primary, foreign)
+
+    const orm = await DALUtils.mikroOrmCreateConnection(dbData, [entity])
+
+    const tableName = entity.meta.collection
+
+    let hasTable = false
+    try {
+      await orm.em.getConnection().execute(`SELECT 1 FROM ${tableName} LIMIT 0`)
+      hasTable = true
+    } catch {}
+
+    const generator = orm.getSchemaGenerator()
+    if (hasTable) {
+      const updateSql = await generator.getUpdateSchemaSQL()
+      const entityUpdates = updateSql
+        .split(";")
+        .map((sql) => sql.trim())
+        .filter((sql) =>
+          sql.toLowerCase().includes(`alter table "${tableName.toLowerCase()}"`)
+        )
+
+      if (entityUpdates.length > 0) {
+        try {
+          await generator.execute(entityUpdates.join(";"))
+          logger.info(`Link module "${serviceName}" migration executed`)
+        } catch (error) {
+          logger.error(
+            `Link module "${serviceName}" migration failed to run - Error: ${error}`
+          )
+        }
+      } else {
+        logger.info(`Skipping "${tableName}" migration.`)
+      }
+    } else {
+      try {
+        await generator.createSchema()
+
+        logger.info(`Link module "${serviceName}" migration executed`)
+      } catch (error) {
+        logger.error(
+          `Link module "${serviceName}" migration failed to run - Error: ${error}`
+        )
+      }
+    }
+
+    await orm.close()
+  }
+}