Update 2.x docs about support policy for ingress - 2nd try

[kunisen]

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• 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

It's a clone of #8582 but targets at ECK 2.16 branch as suggested in #8582 (comment)

• 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.

[kunisen]

Thanks @barkbay for your suggestion in #8582 (comment). Could you kindly help check if this is the correct way to file doc PR please?

[barkbay]

LGTM

[kunisen]

Thanks! @barkbay could you kindly help merge this as I am not seemingly authorized to push to this branch.