chore(): Reorganize modules (#7210)

**What**
Move all modules to the modules directory

packages/modules/customer/src/models/customer-group-customer.ts

@@ -0,0 +1,77 @@
+import { DAL } from "@medusajs/types"
+import { generateEntityId } from "@medusajs/utils"
+import {
+  Cascade,
+  BeforeCreate,
+  ManyToOne,
+  Entity,
+  OnInit,
+  OptionalProps,
+  PrimaryKey,
+  Property,
+} from "@mikro-orm/core"
+import Customer from "./customer"
+import CustomerGroup from "./customer-group"
+
+type OptionalGroupProps = "customer_group" | "customer" | DAL.EntityDateColumns // TODO: To be revisited when more clear
+
+@Entity({ tableName: "customer_group_customer" })
+export default class CustomerGroupCustomer {
+  [OptionalProps]: OptionalGroupProps
+
+  @PrimaryKey({ columnType: "text" })
+  id!: string
+
+  @Property({ columnType: "text" })
+  customer_id: string
+
+  @Property({ columnType: "text" })
+  customer_group_id: string
+
+  @ManyToOne({
+    entity: () => Customer,
+    fieldName: "customer_id",
+    index: "IDX_customer_group_customer_customer_id",
+    cascade: [Cascade.REMOVE],
+  })
+  customer: Customer
+
+  @ManyToOne({
+    entity: () => CustomerGroup,
+    fieldName: "customer_group_id",
+    index: "IDX_customer_group_customer_group_id",
+    cascade: [Cascade.REMOVE],
+  })
+  customer_group: CustomerGroup
+
+  @Property({ columnType: "jsonb", nullable: true })
+  metadata: Record<string, unknown> | null = null
+
+  @Property({
+    onCreate: () => new Date(),
+    columnType: "timestamptz",
+    defaultRaw: "now()",
+  })
+  created_at: Date
+
+  @Property({
+    onCreate: () => new Date(),
+    onUpdate: () => new Date(),
+    columnType: "timestamptz",
+    defaultRaw: "now()",
+  })
+  updated_at: Date
+
+  @Property({ columnType: "text", nullable: true })
+  created_by: string | null = null
+
+  @BeforeCreate()
+  onCreate() {
+    this.id = generateEntityId(this.id, "cusgc")
+  }
+
+  @OnInit()
+  onInit() {
+    this.id = generateEntityId(this.id, "cusgc")
+  }
+}