Move mimetype definitions to plugin specs

- Avoids the hassle of QRC files and manually registering mime types
- Avoids performance regressions because of mime types that are
  registered after mime database has been used
- Makes it technically possible to detect that a disabled plugin could
  handle a mime type if it was enabled

Change-Id: I373008b1b56e9c6b4853055f20b3eeb112a6eff9
Reviewed-by: Christian Stenger <christian.stenger@qt.io>
Reviewed-by: hjk <hjk@qt.io>

src/plugins/pythoneditor/pythoneditorplugin.cpp

@@ -52,7 +52,6 @@
 
 #include <utils/algorithm.h>
 #include <utils/detailswidget.h>
-#include <utils/mimetypes/mimedatabase.h>
 #include <utils/pathchooser.h>
 #include <utils/qtcprocess.h>
 #include <utils/utilsicons.h>
@@ -885,8 +884,6 @@ bool PythonEditorPlugin::initialize(const QStringList &arguments, QString *error
     Q_UNUSED(arguments)
     Q_UNUSED(errorMessage)
 
-    MimeDatabase::addMimeTypes(":/pythoneditor/PythonEditor.mimetypes.xml");
-
     addAutoReleasedObject(new PythonProjectManager);
     addAutoReleasedObject(new PythonEditorFactory);
     addAutoReleasedObject(new PythonRunConfigurationFactory);