Build configs for preview builds through GKE
## Description ✍️
Moving the docs preview builds from Cloudflare to "websitecloud" Google Cloud Project which is currently handling the staging and production deployments:
The preview triggers are expected to be called only on changes to the docs folder
PR-URL: https://github.com/hasura/graphql-engine-mono/pull/6999
GitOrigin-RevId: 1699fe7677ebc03b8ce6338394e91d8e848640c3
