Move methods from Command to AbstractPDOCmmand class

[Tigrov]

Related with yiisoft/db#770

Q	A
Is bugfix?	❌
New feature?	❌
Breaks BC?	❌
Fixed issues	-

[what-the-diff]

PR Summary

• Removal of the getQueryBuilder() method
  The getQueryBuilder() method was removed from the Command class. This was done because it was not being used.

• Cleanup of the internalExecute() method
  The internalExecute() method was updated to remove redundant code and exception handling related to transactions and retry logic.

• Removal of unused import statements
  Several import statements were removed because they were not being used in the current code. These include import statements for PDOException, Throwable, ConvertException, QueryBuilderInterface, QueryBuilder, PDO, SchemaInterface, array_keys, AbstractPdoCommand.

• Refactoring bindPendingParams() method
  The bindPendingParams() method was updated to remove the $rawSql parameter and associated code to make it more efficient.

• Modification of showDatabases() method
  The showDatabases() method no longer has a return type declaration. This change was made for better compatibility with different types of databases.

Provided changes aim to clean up the code, remove unnecessary elements, and enhance efficiency. This should provide a cleaner, faster release of this software.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (5ecee24) 98.44% compared to head (7cd697b) 98.39%.

Additional details and impacted files

@@             Coverage Diff              @@
##             master     #243      +/-   ##
============================================
- Coverage     98.44%   98.39%   -0.06%     
+ Complexity      184      174      -10     
============================================
  Files            16       16              
  Lines           580      561      -19     
============================================
- Hits            571      552      -19     
  Misses            9        9              

Files	Coverage Δ
src/Command.php	97.91% <ø> (-0.60%)	⬇️

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