Support KMS asymmetric keys

Hello,

I am unable to figure out few things while using kms. I have the following use case:

1. GenerateDataKeyPairWithoutPlainText - CLI
2. Store the above generated keys in the AWS secret manager - Console
3. Fetch the public key and give it to the client - Java
4. Client encrypts data and send it to us.- Java
5. We fetch the private key from the secret manager and decrypt data sent to us by client. - Java

I have executed the first three steps and need a Java Example for the last two. Thanks!

Start by reviewing the GenerateDataKeyPairWithoutPlainText workflow described in the issue and the Java integration point for the final encryption and decryption steps. A useful result would document how the client encrypts with the public key and how the service retrieves the private key from AWS Secrets Manager to decrypt the data.

Written by the indexing model from the issue text.