docs: fix docs to use correct file extension name

[edersonbrilhante]

Description

Standardizes Forge example configuration file extensions on .yml and updates the related Terragrunt/HCL references so example deployments continue to load the renamed files correctly.

This covers deployment examples for Forge EKS, Forge Extras, Forge Integrations, Forge Tenant, Splunk deployment, infra-forge, and reusable templates.

The change removes mixed .yaml/.yml naming in examples without changing configuration contents or runtime behavior.

Type of Change

• Bug Fix
• New Feature
• Breaking Change
• Refactor
• Documentation
• Other: example configuration filename cleanup

Checklist

• I have read the contributing guidelines
• Existing issues have been referenced (where applicable; no related issue found)
• I have verified this change is not present in other open pull requests
• Functionality is documented (not applicable; no new runtime functionality)
• All code style checks pass
• New code contribution is covered by automated tests (not applicable; no new code)
• All new and existing tests pass

Validation

• Not run locally; this is a filename/reference-only examples change.
• PR CI is expected to validate formatting and static checks.