23.0-cppcheck-OutputStreamAthenaPool

Solving last cppcheck defects in the /Database path;

• Member variable 'EventInfoAttListTool::m_attribListSpec' is not initialized in the constructor.
• Either the condition 'ncolumn==names.size()' is redundant or 'ncolumn' can have the value names.size()
• Returning object that will be invalid when returning.

replaced one instance of counting things in a container with the count_if algorithm; tidied headers a little.