Author installation docs for scripts/non-human installations

Currently our docs our docs are optimized for interactive installation via a user's terminal. We need better docs and links for scripts/unattended installations of Radius.

There's one page we have: https://docs.radapp.io/guides/deploy-apps/howto-deploy/howto-deploy-cicd/, but we need to link to this better.

I propose we do the following:

• Do a once over of https://docs.radapp.io/guides/deploy-apps/howto-deploy/howto-deploy-cicd/ to make sure it's up to date and accurate
• Create a friendlier alias for the above page. Something like https://docs.radapp.io/install/script
• Update the rad init long description to include information about unattended installation, and have a link to the page in the docs (the shorter version)
• Update the installation page with a link to the unattended version.

AB#10863

Start by reviewing the existing CI/CD installation page linked in the issue for accuracy and identify the installation page and rad init long description mentioned in the checklist. Create a friendlier unattended-installation entry point, add the requested links, and verify that the documentation and CLI text consistently direct users to the unattended workflow.