Provide function for manualChunks

Instead of hardcoding the manualChunks this allows us to reduce chunk
size of index, and make it more flexible for new dependencies.

vite.config.ts

@@ -42,32 +42,16 @@ export default defineConfig({
     outDir: "build",
     rollupOptions: {
       output: {
-        manualChunks: {
-          markdown: [
-            "@radicle/gray-matter",
-            "dompurify",
-            "hast-util-to-dom",
-            "hast-util-to-html",
-            "katex",
-            "marked",
-          ],
-          syntax: ["@wooorm/starry-night"],
-          grammarsTsx: [
-            "@wooorm/starry-night/source.ts",
-            "@wooorm/starry-night/source.tsx",
-          ],
-          grammars: [
-            "@wooorm/starry-night/source.python",
-            "@wooorm/starry-night/source.js",
-            "@wooorm/starry-night/source.perl",
-            "@wooorm/starry-night/source.haskell",
-            "@wooorm/starry-night/source.ruby",
-            "@wooorm/starry-night/source.css",
-            "@wooorm/starry-night/source.solidity",
-            "@wooorm/starry-night/source.cs",
-            "@wooorm/starry-night/source.swift",
-          ],
-          dom: ["svelte", "twemoji"],
+        manualChunks: id => {
+          if (id.includes("lodash")) {
+            return "lodash";
+          } else if (id.includes("katex")) {
+            return "katex";
+          } else if (id.includes("node_modules")) {
+            return "vendor";
+          } else if (id.includes("components")) {
+            return "components";
+          }
         },
       },
     },