Cleanup Old Grails.org and GitHub.io URLs

[sanjana2505006]

Based on our discussion in #392, I have updated conf/modules.yml to point to the correct documentation URL you provided:
https://grails.github.io/grails-data-graphql/latest/hibernate/guide/index.html

Also, I realised I missed updating an insecure http:// link to https:// in my previous security PR, so I have included that fix here for pages/maturity.html to keep things tidy.

This PR fixes issue #392

[jamesfredley]

@sanjana2505006 For this PR

Let's undo the line wrapping changes in the HTML, since those do not change the output and make the PR harder to review.

There are many additional URL which can be updated from the issue:

https://github.com/search?q=repo%3Aapache%2Fgrails-static-website%20.grails.org&type=code

on these old .grails.org subdomains, for the ones which are redirected the new URLs that looks like https://grails.apache.org/docs-legacy-*/*.

If needed we can also fix any existing redirects for the old subdomains to https://grails.apache.org/docs-legacy-*/*:

https://github.com/grails/grails-testing-support
https://github.com/grails/grails-gsp
https://github.com/grails/grails-async
https://github.com/apache/grails-data-mapping
https://github.com/apache/grails-views

https://github.com/search?q=repo%3Aapache%2Fgrails-static-website+github.io&type=code

On this list, many of these are fine and do not need to be updated. But some have a new URL.

IE. https://grails.github.io/grails-views/latest/ which returns a 404, the new URL is https://apache.github.io/grails-views/latest/ which then redirects a few times to the final URL which we should use https://grails.apache.org/docs/latest/guide/theWebLayer.html#gson

https://grails.github.io/ changed to https://apache.github.io/ for all the Grails repos that moved to Apache.

[sanjana2505006]

@jamesfredley Thank you for the detailed review.

I’ll revert the HTML line-wrapping changes so the diff is easier to review.
For this PR, I’ll keep the scope limited to the URLs already updated here. I’ll open follow-up PR(s) to address the additional legacy .grails.org and github.io URLs you mentioned, using the new grails.apache.org/docs-legacy-* and apache.github.io links where applicable.

Let me know if you’d prefer me to include any of those specific updates in this PR instead.

[sanjana2505006]

@jamesfredley I’ve rebased the branch, squashed all changes into a single commit, and updated it according to the requirements. Please let me know if anything else needs adjustment.