feat: Integrate Zipkin tracer

[tobbbles]

Updates the ory/x/tracing package to the latest version, configures the provider to parse config file and envvar configuration for Zipkin, integrates the tracer

Related issue(s)

Checklist

• I have read the contributing guidelines.
• I am following the
  contributing code guidelines.
• I have read the security policy.
• I confirm that this pull request does not address a security
  vulnerability. If this pull request addresses a security. vulnerability, I
  confirm that I got green light (please contact
  [email protected]) from the maintainers to push
  the changes.
• I have added tests that prove my fix is effective or that my feature
  works.
• I have added or changed the documentation.

Further Comments

The go.mod replace directive for updating just the tracing package is horrible, but there is no straight upgrade path for the ory/x package, since it still relies on the viperx package. I'd be happy to discuss the semantics around this and oathkeeper

[codecov]

Codecov Report

Merging #832 (c12c716) into master (7504e1e) will increase coverage by 0.03%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #832      +/-   ##
==========================================
+ Coverage   62.39%   62.42%   +0.03%     
==========================================
  Files         102      102              
  Lines        4789     4793       +4     
==========================================
+ Hits         2988     2992       +4     
  Misses       1528     1528              
  Partials      273      273              

Impacted Files	Coverage Δ
driver/configuration/provider_viper.go	86.59% <100.00%> (+0.21%)	⬆️
driver/registry_memory.go	89.91% <100.00%> (+0.04%)	⬆️

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[aeneasr]

Wow! I didn’t know it was possible to update sub-packages like that!

[tobbbles]

Wow! I didn’t know it was possible to update sub-packages like that!

@aeneasr This made me think, and unfortunately - it's not possible! 😞 The go build ignore the replace step, but go get errors out since x/tracing itself isn't a module :(

I've updated the PR to remove this replace, and instead only upgraded ory/x to v0.0.165, the last tag before viperx got removed.

To clarify, what's the plan for Oathkeeper going forward with the removal of viperx?

[aeneasr]

To clarify, what's the plan for Oathkeeper going forward with the removal of viperx?

We want to move it also to Koanf as it is a much better system but are lacking resources to do so, as it would culminate in a larger refactoring of the internals.