feat(migration): add an option to migrate from prismlauncher (#154)

Author: so5iso4ka

launcher/Application.cpp

@@ -598,6 +598,10 @@ Application::Application(int& argc, char** argv) : QApplication(argc, argv)
     {
         bool migrated = false;
 
+        if (!migrated)
+            migrated = handleDataMigration(
+                dataPath, FS::PathCombine(QStandardPaths::writableLocation(QStandardPaths::AppDataLocation), "../../PrismLauncher"),
+                "Prism Launcher", "prismlauncher.cfg");
         if (!migrated)
             migrated = handleDataMigration(
                 dataPath, FS::PathCombine(QStandardPaths::writableLocation(QStandardPaths::AppDataLocation), "../../PolyMC"), "PolyMC",