chore(): Reorganize modules (#7210)

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

packages/modules/cache-inmemory/src/index.ts

@@ -0,0 +1,12 @@
+import { ModuleExports } from "@medusajs/modules-sdk"
+import InMemoryCacheService from "./services/inmemory-cache"
+
+const service = InMemoryCacheService
+
+const moduleDefinition: ModuleExports = {
+  service,
+}
+
+export default moduleDefinition
+export * from "./initialize"
+export * from "./types"