OpenTelemetry
This implements an OpenTelemetry client that integrates with Hindsight.
It updates the server's instrumentation to primarily use OpenTelemetry.
It provides some command line options to the server
binary to specify which OpenTelemetry tracing to use.
Jaeger is NOT CURRENTLY IMPLEMENTED.
The previous hard-coded Hindsight instrumentation is all commented out. It will be re-instated in a future update.