[8.x] terraform: add tags module (backport #15303)

[mergify]

Motivation/summary

The current CI integration with the Terraform ec_deployment uses OIDC; hence, it uses the robots automation, but unfortunately, if ephemeral:true is not set and the tear-down steps fail in the CI, those resources are not deleted automatically but manually.

We want to enforce using ephemeral:true in all the Terraform resources using ec, the ephemeral:true was added as part of #14179

But I didn't see the tags to be set for the cloud and functional tests that run in the CI or can run.

Checklist

• Update CHANGELOG.asciidoc
• Documentation has been updated

For functional changes, consider:

• Is it observable through the addition of either logging or metrics?
• Is its use being published in telemetry to enable product improvement?
• Have system tests been added to avoid regression?

How to test these changes

Related issues

---

This is an automatic backport of pull request #15303 done by [Mergify](https://mergify.com).