Replace StyleCI with PHP CS Fixer

[mspirkov]

Q	A
Is bugfix?	❌
New feature?	❌
Breaks BC?	❌
Fixed issues	comma-separated list of tickets # fixed by the PR, if any

[codecov]

Codecov Report

❌ Patch coverage is 94.11765% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 95.87%. Comparing base (e59b05f) to head (445021d).
⚠️ Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
src/Debug/AuthenticationMethodInterfaceProxy.php	0.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master     #105      +/-   ##
============================================
+ Coverage     95.81%   95.87%   +0.06%     
  Complexity       77       77              
============================================
  Files            10       10              
  Lines           191      194       +3     
============================================
+ Hits            183      186       +3     
  Misses            8        8              

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