Draft: Resolve "Build and ship Developer Experience landing page"

Step 1: What is changing in this MR?

Production	Review app
N/A	https://3604-devex.about.gitlab-review.app/developer-experience/

Step 2: Ensure that your changes comply with the following, where applicable:

• I, the Assignee, have run Axe tools on any updated pages, and fixed the relevant accessibility issues.
• These changes work on both Safari, Chrome, and Firefox.
• These changes have been reviewed for Visual Quality Assurance and Functional Quality Assurance on Mobile, Desktop, and Tablet.
• These changes work with our Google Analytics and SEO tools.
• These changes have been documented as expected.

Build Variables:

• Use Contentful Preview API

Related #3604

Related https://gitlab.com/gitlab-com/marketing/digital-experience/buyer-experience/-/issues/3578