Add Provider Support for Cloud-based Parameter Stores (e.g., AWS SSM, GCP Parameter Manager, Azure App Config)

Description:
OpenFeature currently supports various providers for feature flag management. It would be valuable to extend this support by adding a provider (or a set of providers) for cloud-native parameter stores, which are commonly used in enterprise environments for storing configuration and secrets.

These parameter/configuration stores include:

• AWS Systems Manager Parameter Store
• Google Cloud Parameter/Secret Manager Manager
• Azure App Configuration / Key Vault

Adding support for these services would enable OpenFeature users to:

1. Leverage existing cloud-native infrastructure
2. Dynamically fetch feature flags or configuration values stored in these systems
3. Improve consistency and reduce duplication across infrastructure and application layers

Proposed Solution:
Implement a separate providers per cloud that can:

1. Connect securely to the respective parameter/config store
2. Fetch values at runtime (optionally cache them)
3. Map keys to OpenFeature flag format
4. Handle authentication via cloud-native SDKs (IAM roles, service accounts, etc.)

Benefits:

1. Seamless integration with existing cloud infrastructure
2. Improved developer experience for cloud-first teams
3. Encourages unified configuration management practices

Potential Challenges:

• Differences in data models and access patterns across cloud platforms
• Managing credentials securely across environments
• Standardizing behavior for flag evaluation

Related Links:
AWS Parameter Store
GCP Parameter Manager
Azure App Configuration

Notes:
If there's alignment with the OpenFeature roadmap, I’d be happy to collaborate on a proposal or contribute a reference implementation.

No files, tests, or entry points are named. Start by reviewing the linked AWS, GCP, and Azure documentation and checking the OpenFeature roadmap to define whether one provider or separate providers are in scope. Done should include an agreed scope for secure access, runtime fetching, key mapping, caching, and standardized flag evaluation.