feat: factor accesstoken runtime-dependency wrapper out

[eisber]

What changes are proposed in this pull request?

Factor accesstoken wrapper into a separate class so it can be consumed by others as well.

How is this patch tested?

Certified event tests

[github-actions]

Hey @eisber 👋!
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Someone from SynapseML Team will be reviewing this pull request soon.

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[eisber]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[codecov-commenter]

Codecov Report

Merging #2097 (49df5da) into master (3fc47ae) will decrease coverage by 0.03%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##           master    #2097      +/-   ##
==========================================
- Coverage   86.29%   86.27%   -0.03%     
==========================================
  Files         309      310       +1     
  Lines       16254    16254              
  Branches      833      826       -7     
==========================================
- Hits        14027    14023       -4     
- Misses       2227     2231       +4     

Files	Coverage Δ
...napse/ml/logging/fabric/CertifiedEventClient.scala	36.84% <0.00%> (+9.39%)	⬆️
...crosoft/azure/synapse/ml/fabric/TokenLibrary.scala	0.00% <0.00%> (ø)

... and 4 files with indirect coverage changes