chore(): Reorganize modules (#7210)

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

packages/modules/payment/src/loaders/providers.ts

@@ -0,0 +1,40 @@
+import { moduleProviderLoader } from "@medusajs/modules-sdk"
+import { LoaderOptions, ModuleProvider, ModulesSdkTypes } from "@medusajs/types"
+import { Lifetime, asFunction, asValue } from "awilix"
+
+import * as providers from "../providers"
+
+const registrationFn = async (klass, container, pluginOptions) => {
+  Object.entries(pluginOptions.config || []).map(([name, config]) => {
+    const key = `pp_${klass.PROVIDER}_${name}`
+
+    container.register({
+      [key]: asFunction((cradle) => new klass(cradle, config), {
+        lifetime: klass.LIFE_TIME || Lifetime.SINGLETON,
+      }),
+    })
+
+    container.registerAdd("payment_providers", asValue(key))
+  })
+}
+
+export default async ({
+  container,
+  options,
+}: LoaderOptions<
+  (
+    | ModulesSdkTypes.ModuleServiceInitializeOptions
+    | ModulesSdkTypes.ModuleServiceInitializeCustomDataLayerOptions
+  ) & { providers: ModuleProvider[] }
+>): Promise<void> => {
+  // Local providers
+  for (const provider of Object.values(providers)) {
+    await registrationFn(provider, container, { config: { default: {} } })
+  }
+
+  await moduleProviderLoader({
+    container,
+    providers: options?.providers || [],
+    registerServiceFn: registrationFn,
+  })
+}