switch from gulp to vite to build, add types for reveal.js config

plugin/zoom/vite.config.ts

@@ -0,0 +1,22 @@
+import { resolve } from 'path';
+import { defineConfig } from 'vite'
+import { appendExtension } from '../../vite.config.ts';
+
+// Once Vite supports multiple entries for plugins, this build can
+// be merged into the main vite.config.ts.
+// See https://github.com/vitejs/vite/pull/10609
+
+export default defineConfig({
+  build: {
+    emptyOutDir: false,
+    lib: {
+      formats: ['es', 'umd'],
+      entry: {
+        'plugin/zoom': resolve(__dirname, 'index.js'),
+      },
+      name: 'RevealZoom',
+      fileName: appendExtension
+    }
+  },
+  plugins: [],
+})