CppTools: Move ProjectPart in its own header file

Also extracting inline HeaderPath class and change projects list in vector
because the size is  larger than a pointer.

Change-Id: I885fdff3fe9bccc877634d1615249755f5b674fd
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@theqtcompany.com>

src/plugins/cpptools/cppprojectfile.h

@@ -75,7 +75,7 @@ namespace Internal {
 class ProjectFileAdder
 {
 public:
-    ProjectFileAdder(QList<ProjectFile> &files);
+    ProjectFileAdder(QVector<ProjectFile> &files);
     ~ProjectFileAdder();
 
     bool maybeAdd(const QString &path);
@@ -84,7 +84,7 @@ private:
 
     void addMapping(const char *mimeName, ProjectFile::Kind kind);
 
-    QList<ProjectFile> &m_files;
+    QVector<ProjectFile> &m_files;
     QHash<QString, ProjectFile::Kind> m_mimeNameMapping;
 };