demo: re-add netlify.toml for demo

exampleSite/netlify.toml

@@ -0,0 +1,26 @@
+[build]
+  command = "hugo --gc --minify -b $URL"
+  publish = "public"
+
+[build.environment]
+  HUGO_VERSION = "0.79.1"
+  HUGO_ENABLEGITINFO = "true"
+
+[context.production.environment]
+  HUGO_ENV = "production"
+
+[context.deploy-preview]
+  command = "hugo --gc --minify --buildFuture -b $DEPLOY_PRIME_URL"
+
+[context.branch-deploy]
+  command = "hugo --gc --minify -b $DEPLOY_PRIME_URL"
+
+[[headers]]
+  for = "*.webmanifest"
+  [headers.values]
+    Content-Type = "application/manifest+json; charset=UTF-8"
+
+[[headers]]
+  for = "index.xml"
+  [headers.values]
+    Content-Type = "application/rss+xml"