Use Getting Started as the landing page with azd code demo GIF

[hemarina]

Parent issue: #792

Redirect the landing page to the Getting Started page and then navigate users to the template gallery from there. Include an animated GIF that demonstrates actual azd commands in action so users can immediately see the developer experience.

[haileyhuber8]

Developers should land on the home page as an azd page - how to get started. Landing here should tell me in very few words and distractions what superpower azd will give me and immediately see the CTA to start with it. Heavily developer startup branded, lots of great examples out there.

• branding is azd focused
• large, centralized tagline: "from code to cloud in minutes"
• main CTA to get started is azd init, secondary lower? option to browse templates which sends you to the template gallery page
• scroll for the gif with text to the side of what azd can help you do (showcase extension in use, azd up a template, etc.)