docs: Data Balance documentation updates

[martthalch]

Updated data balance main documentation to integrate the feedback from the fairness committee in MS. Data Balance is a tool, but it does not completely solves for fairness. In combination with other tools it helps reduce fairness related harms, but there is no way to way a completely unbiased dataset or model.

Updated the notebook to reduce the amount of measure explanations and better introduce the goals of data balance analysis.

AB#1839731

[mhamilton723]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[codecov-commenter]

Codecov Report

Merging #1540 (9c182df) into master (3bd5bef) will decrease coverage by 7.12%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1540      +/-   ##
==========================================
- Coverage   83.74%   76.62%   -7.13%     
==========================================
  Files         301      294       -7     
  Lines       15337    15202     -135     
  Branches      707      707              
==========================================
- Hits        12844    11648    -1196     
- Misses       2493     3554    +1061     

Impacted Files	Coverage Δ
...soft/azure/synapse/ml/cognitive/AudioStreams.scala	0.00% <0.00%> (-87.88%)	⬇️
...synapse/ml/cognitive/TextAnalyticsSDKSchemas.scala	0.00% <0.00%> (-81.20%)	⬇️
...e/synapse/ml/cognitive/FormRecognizerSchemas.scala	7.69% <0.00%> (-76.93%)	⬇️
...t/azure/synapse/ml/cognitive/SpeechToTextSDK.scala	16.47% <0.00%> (-74.12%)	⬇️
...ure/synapse/ml/cognitive/FormOntologyLearner.scala	14.28% <0.00%> (-73.47%)	⬇️
...crosoft/azure/synapse/ml/cognitive/SpeechAPI.scala	0.00% <0.00%> (-70.00%)	⬇️
.../azure/synapse/ml/cognitive/TextAnalyticsSDK.scala	20.27% <0.00%> (-67.14%)	⬇️
.../synapse/ml/cognitive/AnomalyDetectorSchemas.scala	33.33% <0.00%> (-66.67%)	⬇️
...oft/azure/synapse/ml/cognitive/TextAnalytics.scala	24.80% <0.00%> (-64.13%)	⬇️
...ft/azure/synapse/ml/cognitive/TextTranslator.scala	26.69% <0.00%> (-54.52%)	⬇️
... and 26 more

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