abstraction: use unique_ptr only to manipulate operation::Abstraction

alib2abstraction/src/common/CastHelper.cpp

alib2abstraction/src/common/EvalHelper.cpp

alib2abstraction/src/common/EvalHelper.h

alib2cli/src/ast/command/PrintCommand.cpp

alib2cli/src/ast/statements/ContainerStatement.cpp

alib2cli/src/ast/statements/FileStatement.cpp

alib2cli/src/ast/statements/ResultFileStatement.h

alib2gui/src/Converter.cpp