[FR] Add Tag Support to x-logging

[DonIsiko]

Summary

Add the ability to define service-specific tags for CloudWatch Log Groups created via x-logging, bringing it into alignment with other x-* features like x-alarms and x-dynamo.

Current Limitation

Currently, when defining x-logging for a service, there is no way to add service-specific tags to the CloudWatch Log Group. Global tags from x-tags are applied, but additional service-level tags cannot be specified, unlike other x-* resources (x-alarms, x-dynamo, etc.) which support Properties.Tags.

Discussed Solutions

Option 1: Shorthand Syntax (Simpler)

Add direct tag support at the x-logging level:

services:
  my-app:
    x-logging:
      RetentionInDays: 30
      Tags:
        - Key: Environment
          Value: production
        - Key: Sensitivity
          Value: high

Option 2: Full LogGroup Support (More Flexible)

Support full CloudFormation properties and lookup capabilities:

services:
  my-app:
    x-logging:
      LogGroup:
        Properties:
          RetentionInDays: 30
          Tags:
            - Key: Environment
              Value: production
        # OR
        Lookup:
          Tags:
            - Key: Name
              Value: existing-log-group

Personal preference

Implement option 2:

• When LogGroup is defined, expect full CFN Properties or Lookup syntax

Expected Behaviour

• Service-specific tags should be merged with global x-tags
• Tags from x-logging should supplement (not replace) global tags
• Behaviour should be consistent with other x-* features

Benefits

1. Consistency: Aligns x-logging with the established pattern used by newer x-* features
2. Flexibility: Enables advanced Log Group configurations (KMS encryption, confidentiality policies, etc.)
3. Resource Reuse: Lookup functionality would allow reusing existing Log Groups with tag-based discovery
4. Governance: Enables service-specific tagging for cost allocation, compliance, and security classification

Related Issue

Convert from bug report #820

[JohnPreston]

Thanks @DonIsiko
I will support both adding 1 shorthand for tags alone, and then require for LogGroup to be present and itself have Properties or Lookup set :)