Move Guides Publishing to grails.apache.org/guides

[jamesfredley]

Guide Publishing is split between https://github.com/apache/grails-static-website/ and https://github.com/grails-guides/grails-guides-template/. It should likely be consolidated and published to https://grails.apache.org/guides eliminating the need for a separate subdomain guides.grails.org.

https://github.com/apache/grails-static-website/blob/master/.github/workflows/publish.yml#L44-L53 - the grails-static-website has been disabled for now.

Individual guides are published to https://github.com/grails-guides/grails-guides-template/tree/gh-pages using another process, which makes moving this to grails.apache.org non-trivial.

[jamesfredley]

Publishing to legacy location restored on https://github.com/apache/grails-static-website/commit/613ce1ef4a383af5f983114af52fabb0b498563e, https://guides.grails.org/ with the updated Apache site requirements.