Feat(authentication): Load auth providers (#6023)

* initial providers loader implementation

* registerAdd providers

* remove comment

* remove comment

packages/authentication/src/providers/index.ts

@@ -0,0 +1 @@
+export { default as UsernamePasswordProvider } from "./username-password"

packages/authentication/src/providers/username-password.ts

@@ -0,0 +1,21 @@
+import { AuthUserService } from "@services"
+import { AbstractAuthenticationModuleProvider } from "@medusajs/types"
+
+class UsernamePasswordProvider extends AbstractAuthenticationModuleProvider {
+  public static PROVIDER = "usernamePassword"
+  public static DISPLAY_NAME = "Username/Password Authentication"
+
+  protected readonly authUserSerivce_: AuthUserService
+
+  constructor({ authUserService: AuthUserService }) {
+    super()
+
+    this.authUserSerivce_ = AuthUserService
+  }
+
+  async authenticate(userData: Record<string, unknown>) {
+    return {}
+  }
+}
+
+export default UsernamePasswordProvider