docs: add Drupal 7 roadmap page

src/pages/d7.mdx

@@ -0,0 +1,22 @@
+---
+layout: ~/layouts/PageLayout.astro
+title: Drupal 7 upgrade roadmap
+price: £7,500
+button:
+  link: https://buy.stripe.com/8wM9Bk98Kga6dbO149
+  text: Get started
+testimonials:
+  - huw-davies
+  - scott-euser
+  - jon-hallett
+  - brian-hartwell
+---
+
+import Button from "~/components/Button.astro";
+import Testimonials from "~/components/Testimonials.astro";
+
+Price: {frontmatter.price}
+
+<Button href={frontmatter.button.link} text={frontmatter.button.text} />
+
+<Testimonials names={frontmatter.testimonials} />