Update copyright style across all AWS Encryption SDK

To follow this style:
```
/**
* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
* SPDX-License-Identifier: Apache-2.0.
*/
```
Configure CI to verify it [1] [2]

[1] https://github.com/awslabs/aws-encryption-sdk-specification/blob/4b1c0e06435d385fc0593a5619ce686cf2cb79e8/.github/workflows/ci_static-analysis.yaml#L7-L12
[2] https://github.com/awslabs/aws-encryption-sdk-specification/blob/master/.github/not-grep.toml

Inspect the repository’s C source files and CI configuration, using the linked specification workflow and .github/not-grep.toml as references for the intended check. Update the copyright headers across the SDK and configure CI to verify the required style; done means all applicable files conform and CI detects deviations.

Written by the indexing model from the issue text.