Update middleware function to correctly honor trace headers

[renaz6]

• With the newest Tr1d1um release, tracing headers can now be sent in WRP messages (which can be sent as Xmidt headers, JSON, or msgpack)
• This PR updates Candlelight with capability to get the trace headers (if they exist) using the new wrpcontext package. Candlelight then propagates the trace context with this info so that remote spans can be honored and not broken.
• Also updated the header names to have the correct prefix. Closes Ensure Correct Xmidt Header Usage #117

[guardrails]

All previously detected findings have been fixed. Good job! 👍🎉

We will keep this comment up-to-date as you go along and notify you of any security issues that we identify.

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[codecov]

Codecov Report

Merging #115 (3388f3f) into main (866e9f7) will decrease coverage by 5.66%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##             main     #115      +/-   ##
==========================================
- Coverage   77.20%   71.55%   -5.66%     
==========================================
  Files           4        4              
  Lines         215      232      +17     
==========================================
  Hits          166      166              
- Misses         44       61      +17     
  Partials        5        5              

Flag	Coverage Δ
unittests	71.55% <0.00%> (-5.66%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
middleware.go	14.89% <0.00%> (-8.44%)	⬇️

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[sonarcloud]

SonarCloud Quality Gate failed.   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

0.0% Coverage
0.0% Duplication

[denopink]

left some questions, but overall lgtm 🍻