Update validation middleware

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

src/server/validations/artists.validation.ts

@@ -0,0 +1,30 @@
+import { z } from 'zod';
+import { AlbumSort } from '../helpers/albums.helpers';
+import {
+  idValidation,
+  orderByValidation,
+  paginationValidation,
+  serverFolderIdValidation,
+} from './shared.validation';
+
+const list = {
+  body: z.object({}),
+  params: z.object({}),
+  query: z.object({
+    ...paginationValidation,
+    ...serverFolderIdValidation,
+    ...orderByValidation,
+    sortBy: z.nativeEnum(AlbumSort),
+  }),
+};
+
+const detail = {
+  body: z.object({}),
+  params: z.object(idValidation),
+  query: z.object({}),
+};
+
+export const artistsValidation = {
+  detail,
+  list,
+};