Add CTA for local preview under /self-hosted install now button

[MichaelAring]

Context

• We want to show users that they can try the local preview of self-hosted if the full installation is too complex
• This relates to #9075
• Context in Notion
• Context in Slack

Solution

• Add CTA "Can’t install on K8s? Try Gitpod locally with local preview" below the "Install Now" button on https://www.gitpod.io/self-hosted
• Point link to: https://www.gitpod.io/docs/self-hosted/latest/local-preview

[Pothulapati]

I don’t think we should be pointing to previvew-install repo, as its stale now. The code is now at https://github.com/gitpod-io/gitpod/tree/main/install/preview, while the documentation is at https://www.gitpod.io/docs/self-hosted/latest/local-preview

[lucasvaltl]

Updated the description here to say that the link should point to the docs page

[Siddhant-K-code]

Just wanted to double check this one, is it still needed?

[Siddhant-K-code]

It is resolved by #2972