Add Integration for PagerDuty Alerts from Splunk Cloud & SignalFx

[edersonbrilhante]

Description:
We want Forge to support consuming alerts from Splunk Cloud and Splunk SignalFx and forwarding them to PagerDuty. This would allow our teams to centralize alert notifications and respond faster to critical events.

Proposed Work:

1. Create a Terraform/Forge module to set up the PagerDuty integration.
2. Create another module or set of predefined queries/alerts in Splunk/SFx that the integration will consume.
3. Ensure the integration can handle both logs and metrics alerts.
4. Include multi-tenant support if needed (similar to how Forge handles other services).

Benefits:

• Centralized alert management
• Faster incident response
• Standardized queries and alerts across environments

Optional:

• Provide a way to configure severity mapping from Splunk/SFx to PagerDuty.
• Provide documentation and examples for common alert use cases.

Acceptance Criteria:

• Alerts from Splunk Cloud and SignalFx trigger PagerDuty incidents.
• Modules are reusable and configurable for multiple environments.
• Documentation is provided for setup and usage.