Utils: Extract a CommandLine structure from a QtcProcess

We regularly pass around strings or filenames or pairs of strings
or filenames and stringlist etc the in the end will be used
as a kind of "command line", with quite a bit of ad-hoc user
code and QtcProcess::addArg etc to set them up and manipulate them.

Let's have a class for that concept.

Change-Id: I288ab939d853b32c717135a65242c584c2beab50
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/plugins/cppcheck/cppcheckrunner.cpp

@@ -32,6 +32,8 @@
 
 #include <coreplugin/messagemanager.h>
 
+using namespace Utils;
+
 namespace Cppcheck {
 namespace Internal {
 
@@ -153,7 +155,7 @@ void CppcheckRunner::checkQueued()
     else
         m_queue.begin().value() = files;
 
-    m_process->setCommand(m_binary, arguments);
+    m_process->setCommand(CommandLine(FilePath::fromString(m_binary), arguments));
     m_process->start();
 }