ESC: Add featured capability about integration to targets to product landing page

[thoward]

Relevant page: https://www.pulumi.com/docs/esc/

Per Gavin: On that page, we cover secrets providers in the 4 square feature section, but we should also have a section of cards for targets that consume secrets... See product home page graph for concept of targets. We should determine the language we want to use for this and determine highest value targets to feature.

Work with Gavin on this.

[thoward]

After meeting w/ Gavin we decided to add the following four-up feature targets: AWS, Azure, Vault, GitHub

But I'm now moving this to the backlog because I realized we don't really have pages to link those to right now. Will revisit this when we have documentation in place that matches this concept. Also, I don't think Vault fits the notion of a "target". I'd amend that list to be: Pulumi IaC, Kubernetes, Docker, GitHub Actions