aws-cloudwatch: Make Alarm object aware of metric region

[danifv]

Describe the feature

Alarm objects should be created in the same region as the metric they are set on.
Currently they use the parent stack's region, which might be different than that of the metric.

Deployments attempt to create an alarm in the stack's region, which if different from that of the metric will result in an error.

Use Case

This feature would allow the creation of stacks responsible for creating metrics and alarms across different regions. Currently our workaround is to create stacks for each region, which makes our IaC unnecessarily complex and redundant.

Proposed Solution

No response

Other Information

No response

Acknowledgements

• I may be able to implement this feature request
• This feature might incur a breaking change

CDK version used

2.1000.2 (build bc82193)

Environment details (OS name and version, etc.)

Debian GNU/Linux 12

[pahud]

Yes, we probably need to update the Metric class to make it region-awareness and modify the Alarm constructor to extract and use the metric's region.

Making this a p2. We welcome PRs.