Refactor(medusa): Create a BaseEntity and SoftDeletableEntity base class for common columns (#1315)

* refactor(medusa): Move some column to a base entity to make it easier to add new models without forgetting some columns

* styles(medusa): Cleanup models

* fix(medusa): typings due to model typings update

* feat(medusa): Cleanup models

* fix(medusa): A model must not return the generateId as part of the entity

* fix(medusa): Plugin integration snapshot

* fix(medusa): Typings from discount-rule-migration scripts

* refactor(medusa): Introduct BaseEntity/SoftDeletableEntity that the entity extends

* styles(medusa): Fix models linting

* test(medusa): Fix integration plugin tests

* feat(medusa): Create generateEntityId standalong function utility and update config to properly supprt ts spec files

* feat(medusa): Update entities to use the new utils to generate and apply the id

* test(medusa): Fix test suits

* feat(medusa): Improve generateEntityId utility

packages/medusa/src/utils/__tests__/generate-entity-id.ts

@@ -0,0 +1,26 @@
+import { generateEntityId } from "../generate-entity-id"
+import { Entity, PrimaryColumn } from "typeorm"
+
+@Entity()
+class GenerateIdSpecEntity {
+  @PrimaryColumn()
+  id: string
+}
+
+describe("generateAndApplyEntityId", () => {
+  it('should return the id if already set', () => {
+    const entity = new GenerateIdSpecEntity()
+    entity.id = "fakeId"
+
+    const generatedId = generateEntityId(entity.id, "prefix")
+    expect(generatedId).toBe(entity.id)
+  })
+
+  it('should return the new generated id if not set already', () => {
+    const entity = new GenerateIdSpecEntity()
+
+    entity.id = generateEntityId(entity.id, "prefix")
+    expect(entity.id).toBeTruthy()
+    expect(entity.id).toEqual(expect.stringMatching(/prefix_*/))
+  })
+})