update 2.x docs about support policy for ingress

[kunisen]

• Have you signed the contributor license agreement? => Yes
• Have you followed the contributor guidelines? => Yes
• If you submit code, is your pull request against main? We recommend pull requests against main. We will backport them as needed. => Not a code PR

Description

• Pairing PR of Clarify ECK support scope for ingress controllers docs-content#908.
• Please backport this to 2.16. (Can also be backported to earlier versions, but if it takes time, it's fine to only do it in 2.16)

Doc pages to update - ECK 2.x

• https://www.elastic.co/guide/en/cloud-on-k8s/current/k8s-recipes.html
• https://www.elastic.co/guide/en/cloud-on-k8s/current/k8s-traffic-splitting.html
• https://www.elastic.co/guide/en/cloud-on-k8s/current/k8s-maps.html
• https://www.elastic.co/guide/en/cloud-on-k8s/current/k8s-maps-http-configuration.html#k8s-maps-ingress
• https://www.elastic.co/guide/en/cloud-on-k8s/current/k8s-stack-helm-chart.html#k8s-eck-stack-ingress

Reference pages (already updated) - ECK 3.x

Per elastic/docs-content#908

• https://docs-v3-preview.elastic.dev/elastic/docs-content/tree/main/deploy-manage/deploy/cloud-on-k8s/recipes
• https://docs-v3-preview.elastic.dev/elastic/docs-content/tree/main/deploy-manage/deploy/cloud-on-k8s/requests-routing-to-elasticsearch-nodes
• https://docs-v3-preview.elastic.dev/elastic/docs-content/tree/main/deploy-manage/deploy/cloud-on-k8s/elastic-maps-server
• https://docs-v3-preview.elastic.dev/elastic/docs-content/tree/main/deploy-manage/deploy/cloud-on-k8s/http-configuration#k8s-maps-ingress
• https://docs-v3-preview.elastic.dev/elastic/docs-content/tree/main/deploy-manage/deploy/cloud-on-k8s/managing-deployments-using-helm-chart

Docs preview

All the docs are added with the same piece of content.

[github-actions]

Warning

It looks like this PR modifies one or more .asciidoc files. These files are being migrated to Markdown, and any changes merged now will be lost. See the migration guide for details.

[barkbay]

👋 @kunisen , thanks for you contribution 🙇

Please backport this to 2.16

We can't merge this PR because these files no longer exist. Could you please open a PR against branch 2.16?

Thanks!

[kunisen]

Thanks @barkbay - I opened #8583. Could you kindly help check if this is the correct way to file doc PR please?

(Will close current one accordingly)