This PR adds:

1. New utils-lite code package that provides SdkInternalThreadLocal, a wrapper around threadLocal.
2. Support for trace id propagation using the new utils-lite class

Background

Previously, we implemented trace ID propagation using SLF4J's MDC in PR #6363, but this was
reverted because the MDC interface exists but the implementation is not provided by the SDK, Lambda runtime, or X-Ray SDK.

Solution

Added a small utils-lite utility class that provides thread local key value storage using ThreadLocal<Map<String, String>>. For this case, it allows the Lambda Runtime Interface Client, AWS SDK, and X-Ray SDK to share trace context via this one package, but can extended to other use cases.

Example:

SdkInternalThreadLocal.put("some-value", foo);
String traceId = SdkInternalThreadLocal.get("some-value");
SdkInternalThreadLocal.remove("some-value");
SdkInternalThreadLocal.clear();