Use navroot to render the sitemap (targets `17.x.x`)

[erral]

In #5105 we changed the sitemap component to be rooted to the language.

Instead doing that, in the PR we use the available navroot to do it.

Moreover I have extracted the hardcoded value of 4 used to call the getNavigation action to a siteMapDepth setting.

[netlify[bot]]

✅ Deploy Preview for volto ready!

Name	Link
🔨 Latest commit	b7ae8c09739979c844478b3ff623d810170dedf8
🔍 Latest deploy log	https://app.netlify.com/sites/volto/deploys/65b62666ff796b00081fee64
😎 Deploy Preview	https://deploy-preview-5185--volto.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify site configuration.

[sneridagh]

@erral Sorry, apparently, this got lost in the sea of PRs, merging now!