GH-994 hopefully fix issue with people still using jar mods

Added an 'add mods' button to the version page
Add jar mods now has a very angry nag dialog until it's used successfully
Buttons on version page are rearranged to deemphasize jar mods

application/MultiMC.cpp

@@ -495,6 +495,9 @@ void MultiMC::initGlobalSettings(bool test_mode)
 	m_settings->registerSetting("SettingsGeometry", "");
 
 	m_settings->registerSetting("PagedGeometry", "");
+
+	// Jar mod nag dialog in version page
+	m_settings->registerSetting("JarModNagSeen", false);
 }
 
 std::shared_ptr<LWJGLVersionList> MultiMC::lwjgllist()