refactor: use a content collection for talks

src/content/config.ts

@@ -0,0 +1,20 @@
+import { defineCollection, z } from 'astro:content';
+
+const talkCollection = defineCollection({
+  schema: z.object({
+    description: z.string(),
+    events: z.array(z.object({
+      date: z.string(),
+      location: z.string().optional(),
+      name: z.string(),
+      online: z.boolean().optional(),
+    })),
+    title: z.string(),
+    // TODO: add SpeakerDeck
+    // TODO: add Video
+  }),
+});
+
+export const collections = {
+  'talk': talkCollection,
+};