Describe the bug
Athens already supports tracing via opencensus; but that is no longer supported and deprecated

Expected behavior
Move to opentelemtry in a non-breaking way.

Environment (please complete the following information):

• OS: [e.g. Linux 64bit]
• Go version :
• Proxy version :
• Storage (fs/mongodb/s3 etc.) :

Additional context
Add any other context about the problem here.