Issue Description:
RHOSE needs to be able to provide distributed tracing of events received by and emitted from RHOSE. Research into distributed tracing concluded that there is good support in existing libraries for W3C's trace-context and that RHOSE should therefore also support it.

Acceptance Criteria:

• Existing trace-context information is preserved throughout RHOSE.
• Events received without trace-context information should have it added.

Out of Scope:
Support for trace-context in any library on which RHOSE depends.