Release Caching Cryptographic Materials Manager for Keyrings

[texastony]

Issue

The AWS Encryption SDK for Java (ESDK-Java) prior to 3.x had a non-deprecated Caching Cryptographic Materials Manager (CachingCMM).

As of 3.x, it only has a marked as deprecated CachingCMM,
which only supports the deprecated Master Key Provider interface.

The AWS Encryption SDK for .NET (ESDK-.NET) has never supported the CachingCMM.

Proposed Resolution

Implement the CachingCMM in this library,
the AWS Cryptographic Materials Provider Library (MPL),
and release it so that the ESDKs for Java and .NET use it.

Issues that reference this

• [Question] Migrating from 2.4.1 to 3.0.0 aws-encryption-sdk-java#2035
• [Question] en/decryptData with CryptoMaterialsManager is deprecated, how to migrate to non-deprecated? aws-encryption-sdk-java#2033 (comment)
• .NET caching CMM support forecast aws-encryption-sdk#659

[github-actions]

This issue has not received attention in 1 year. We will close this issue for now. If you think this is in error, please feel free to comment and reopen the issue.

[IngoStrauch2020]

I think this is still needed to be able to use a Caching Cryptographic Materials Manager with the aws-encryption-sdk 3.x