Utils: Modernize further

Many issues, mostly in headers, were not addressed in
e38410b76c

modernize-use-auto
modernize-use-nullptr
modernize-use-override
modernize-use-using
modernize-use-default-member-init
modernize-use-equals-default

Change-Id: I320a51726db881e582b898948d53735ebb06887a
Reviewed-by: hjk <hjk@qt.io>

src/libs/utils/shellcommand.cpp

@@ -503,7 +503,6 @@ void ShellCommand::setOutputProxyFactory(const std::function<OutputProxy *()> &f
 }
 
 ProgressParser::ProgressParser() :
-    m_future(nullptr),
     m_futureMutex(new QMutex)
 { }