Update validation middleware

- Move to separate directory
- Add TypedRequest utility fn
- Utilize as middleware instead of function

src/server/validations/album-artists.validation.ts

@@ -0,0 +1,22 @@
+import { z } from 'zod';
+import { paginationValidation, idValidation } from './shared.validation';
+
+export const list = {
+  body: z.object({}),
+  params: z.object({}),
+  query: z.object({
+    ...paginationValidation,
+    serverFolderIds: z.string().min(1),
+  }),
+};
+
+export const detail = {
+  body: z.object({}),
+  params: z.object({ ...idValidation }),
+  query: z.object({}),
+};
+
+export const albumArtistsValidation = {
+  detail,
+  list,
+};