(bedrock): refactor needed bedrock construct parts to follow best practices from CDK

[krokoko]

Describe the feature

We want to refactor parts of the bedrock construct to follow CDK's best practices: https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md#metrics

From a high level perspective, this includes:

• Agent
• Agent alias
• Agent action group
• Guardrails
• OpenSearch / Aurora

Other parts of the constructs have been recently updated and should already meet the criteria below

This refactoring will provide at least:

• https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md#abstract-base
• https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md#types
• https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md#unions
• https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md#imports
• https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md#grants
• https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md#metrics
• https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md#documentation
• https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md#testing

Use Case

Quality

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