feat: add basic guestbook page

src/pages/guestbook.html

@@ -0,0 +1,39 @@
+---
+title: Guestbook
+description: Remember guestbooks? They're back! In the same form!
+---
+
+Hello and welcome to my guestbook.
+<aside>
+    All entries are manually verified for spam and such.
+</aside>
+<aside>
+    <strong>Heads up</strong>! This page is not fully working yet. If you sign now, your submission might be deleted.
+</aside>
+<form name="contact" netlify netlify-honeypot="bot-field">
+    <label>
+        Name
+        <input type="text" name="name" required />
+    </label>
+    <p>
+        <label>
+            Website or email
+            <input type="text" name="website_or_email" />
+        </label>
+    </p>
+    <p>
+        <label>
+            Message
+            <textarea name="message" required></textarea>
+        </label>
+    </p>
+    <p class="visually-hidden">
+        <label>
+            Don’t fill this out if you’re human:
+            <input name="bot-field" />
+        </label>
+    </p>
+    <p>
+        <button type="submit">Send</button>
+    </p>
+</form>