feat: Allow users to specify a metric display name prefix

[OmerLitov]

Allow users to specify a metric display name prefix, separately from the metric name prefix

[OmerLitov]

this is the implementation for #2040

[nilebox]

Thanks @OmerLitov, could you please trigger the build again, looks like one of the tests failed due to connectivity issue with Maven Central.
e.g.

git commit --amend --no-edit
git push origin --force

[codecov-commenter]

Codecov Report

Merging #2050 into master will decrease coverage by 0.00%.
The diff coverage is 75.00%.

@@             Coverage Diff              @@
##             master    #2050      +/-   ##
============================================
- Coverage     83.06%   83.06%   -0.01%     
  Complexity     2251     2251              
============================================
  Files           319      319              
  Lines         10529    10532       +3     
  Branches       1048     1049       +1     
============================================
+ Hits           8746     8748       +2     
  Misses         1446     1446              
- Partials        337      338       +1     

Impacted Files	Coverage Δ	Complexity Δ
...ats/stackdriver/StackdriverStatsConfiguration.java	100.00% <ø> (ø)	3.00 <0.00> (ø)
...ts/stackdriver/CreateMetricDescriptorExporter.java	75.32% <66.66%> (-0.68%)	12.00 <0.00> (ø)
...er/stats/stackdriver/StackdriverStatsExporter.java	70.73% <100.00%> (+0.36%)	11.00 <0.00> (ø)

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