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/clearcase/clearcaseplugin.cpp

@@ -54,7 +54,6 @@
 #include <projectexplorer/project.h>
 #include <projectexplorer/iprojectmanager.h>
 #include <utils/algorithm.h>
-#include <utils/mimetypes/mimedatabase.h>
 #include <utils/synchronousprocess.h>
 #include <utils/temporarydirectory.h>
 #include <utils/parameteraction.h>
@@ -418,8 +417,6 @@ bool ClearCasePlugin::initialize(const QStringList & /*arguments */, QString *er
     connect(ProgressManager::instance(), &ProgressManager::allTasksFinished,
             this, &ClearCasePlugin::tasksFinished);
 
-    Utils::MimeDatabase::addMimeTypes(QLatin1String(":/clearcase/ClearCase.mimetypes.xml"));
-
     m_settings.fromSettings(ICore::settings());
 
     // update view name when changing active project