Adapt configuration group names to Yii conventions

[vjik]

Q	A
Is bugfix?	❌
New feature?	❌
Breaks BC?	✔️
Fixed issues	yiisoft/app#271

[codecov]

Codecov Report

Base: 78.94% // Head: 79.36% // Increases project coverage by +0.42% 🎉

Coverage data is based on head (dadc58b) compared to base (879e7d1).
Patch has no changes to coverable lines.

❗ Current head dadc58b differs from pull request most recent head 4d5b162. Consider uploading reports for the commit 4d5b162 to get more accurate results

Additional details and impacted files

@@             Coverage Diff              @@
##             master      #72      +/-   ##
============================================
+ Coverage     78.94%   79.36%   +0.42%     
  Complexity      160      160              
============================================
  Files            12       12              
  Lines           475      475              
============================================
+ Hits            375      377       +2     
+ Misses          100       98       -2     

Impacted Files	Coverage Δ
src/ErrorHandler.php	60.00% <0.00%> (+3.07%)	⬆️

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